The condition required for fermentation to occur is when the oxygen levels within a cell are too low for aerobic respiration.
Further Explanation:Cellular respirationThis is the process by which food substances such as glucose are broken down to yield energy in the form of ATP for the cells. The energy is then sued to drive cellular activities such as transport and cell division.Cellular respiration is classified into two;Aerobic respiration.Aerobic respiration is a type of respiration that takes place in living organisms in the presence of oxygen gas. The process involves the breakdown of organic compounds such as glucose to yield energy in the form of ATP and carbon dioxide together with water as byproducts.Anaerobic respiration/Fermentation Anaerobic respiration on the other hand is a type of respiration that occurs in absence of oxygen gas or in presence of low levels of oxygen gas in the cells. It involves the breakdown of organic compounds to form small amount of energy in the form of ATP and ethanol or lactic acid as byproducts.Occurrence.
Aerobic respiration occurs in three stages;
Glycolysis: This is the first stage of aerobic respiration where an organic molecule such as glucose is broken down to form 2 molecules of Acetyl-CoA and net production of 2 ATP molecules. Each glucose molecule yields two molecules of ATP and two molecules of Acetyl-CoA.Kerb's cycle: It is the second phase of aerobic respiration that involves a series of reactions catalyzed by various enzymes. Acetyl-CoA from glycolysis undergoes a series of reaction to produce six molecules of NADH, two molecules of FADH2, together with carbon dioxide and two molecules of ATP.Electron transport chain; This is the final stage of Aerobic respiration, where the six molecules of NADH and two molecules of FADH from Kreb's cycle are used to generate energy in form of ATP. This stage generates 34 molecules of ATP.Anaerobic respiration/Fermentation occurs in two stages;
Glycolysis; One glucose molecule is broken down to pyruvate and two molecules of ATP are formed.Fermentation; This is the second stage of anaerobic respiration, pyruvate from glycolysis can undergo various steps depending on the living organism. It can be converted to ethanol or lactic acid together with carbon dioxide.Keywords: aerobic respiration, anaerobic respiration, Glycolysis, kreb's cycle, Fermentation and Electron transport.
Learn more about:Cellular respiration: https://brainly.com/question/1544781Fermentation: https://brainly.com/question/1544781Aerobic respiration: https://brainly.com/question/1544781Glycolysis; https://brainly.com/question/1544781Kreb's cycle; https://brainly.com/question/1544781Level: High school
Subject: Biology
Topic: Cellular Respiration
Sub topic: Aerobic and anaerobic respiration
What type of bonds link individual amino acids together?
Answer:
peptide bonds
Explanation:
Amino acids are linked together by peptide bonds. A peptide bond is formed in a condensation reaction between the amine (-NH2) and carboxyl (-COOH) groups of two amino acids, releasing a molecule of water. This process repeats to form a protein.
Explanation:Amino acids are linked together through particular types of bonds known as peptide bonds. In the process of protein formation, each amino acid is brought together with the next through a successive series of these bonds. Essentially, the amine group (-NH2) of one amino acid and the carboxyl group (-COOH) of a second amino acid gets connected in a condensation reaction and forms a peptide bond. In this process, a molecule of water is released.
Example
For example, if you are trying to link the amino acid glycine with another amino acid, like alanine, a peptide bond would form between the carboxyl group of glycine and the amine group of alanine. This results in the creation of a short protein chain or peptide.
Learn more about peptide bonds here:https://brainly.com/question/32355776
#SPJ6
Friction is the force that
Answer:
"Dry friction is a force that opposes the relative lateral motion of two solid surfaces in contact."
hopefully this is helpful :3
Unlike a eukaryotic cell, a prokaryotic cell does not have
a. a cell membrane.
b. cytoplasm.
c. a nucleus.
d. DNA.
Prokaryotic cells, unlike eukaryotic cells, do not have a nucleus. They do however, have a cell membrane, cytoplasm, and DNA, which are common features in all cells. option c.
Explanation:Unlike a eukaryotic cell, a prokaryotic cell does not have a nucleus. Prokaryotic cells, such as bacteria, are the simplest form of living organisms and they don't contain a nucleus to store their genetic material, while eukaryotic cells - such as human cells - contain a nucleus where the DNA is housed. Both cell types indeed have a cell membrane and cytoplasm. These common features are fundamental to cell existence and function. Therefore, the answer to your question is option c. a nucleus.
Learn more about Prokaryotic Cell here:https://brainly.com/question/32523876
#SPJ6
HURRY!!!! The science of classifying organisms based on features they share is called _____.
A. the phylum system
B. the domain system
C. classification
D. taxonomy
Answer:
Taxonomy
Explanation:
Taxonomy is science centered on classification of species.
Answer:
Taxonomy
Explanation:
Which of the following galaxies do not have a regular structure? A. Spiral galaxies B. Elliptical and barred spiral galaxies C. Irregular galaxies D. Irregular and elliptical galaxies
Answer:
Correct answer is C. Irregular galaxies
Explanation:
An irregular galaxy is a galaxy which does not have a well-defined structure and is not identical to an elliptical or a spiral galaxy. Irregular galaxies do not fall into any class of the galaxies having a distinct size and shape.
These galaxies are rich in dust and gas and do not have a smooth appearance. They appear rough and chaotic in structure when observed through a telescope. Furthermore, these are the type of galaxies which are still not fully understood by the astronauts.
Answer:
C Irregular Galaxies :)
Explanation:
Unlike Spiral & Elliptical galaxies, an Irregular galaxy does not have a defined shape/structure. Basic astronomy. 100%.
A group of organisms that changes over time is said to
Answer:
The answer is evolution.
A group of organisms that changes over time is said to evolve. Evolution refers to the process where a group of organisms undergoes gradual changes over time, usually leading to species diversification and often increasing complexity.
Explanation:A group of organisms that changes over time can be said to evolve. This relates to the biological concept of evolution. Evolution is the process where an entity, usually a group of living organisms, undergoes gradual changes over time, leading to species diversification and often increasing complexity. For instance, over time, due to natural selection, a group of organisms might develop new abilities or physical characteristics that help them to survive and reproduce better in their environment.
Learn more about Evolution here:https://brainly.com/question/32103283
#SPJ2
tropical rain forests support more species per unit area than any other terrestrial ecosystem. what is one way rain forests are important to the health of the biosphere?
Answer:
Rain forests recycle nutrients. (Apex)
Explanation:
Plants can convert atmospheric carbon dioxide to other carbon based compounds through photosynthesis. Rain forests are the largest carbon revisers and are responsible for most of the oxygen in the atmosphere
Basically they take in carbon dioxide,convert it to oxygen and then release the oxygen back into the environment. Thus helping to prevent the plant from heating up.
Answer:
Their productive organisms quickly recycle nutrients.
in what age range and development area do individuals begin to have a stronge sense of identity and individualism?
age range. type answer her.
development area. type answer here.
Answer:
age range is between 3-6
Explanation:
by this age, human children are opinionated, discovering their own talents, and have a good sense of who they will become as adults.
Answer:
13-19 years old.
Adolescence.
Explanation:
Adolescence (13-19 years of age) is the age group where the individual has a great psychological development and begins to build his own image, creating his identity, changing the relationship with his parents, creating a strong individualism that will be totally connected to a proper and fickle identity.
This strong sense of indivudualism and the search for identity is generally the main factor in the malaise and the feeling of not fitting into the society that adolescents feel during this phase of psychological development.
In a series of experiments, Griffith infected mice with nonvirulent R-strain bacteria and highly virulent S-strain bacteria. Heat-killed S bacteria were nonvirulent. However, the nonvirulent heat-killed S bacteria and the nonvirulent R bacteria together produced a virulent mixture. What did this demonstrate?
A. The molecules present on the outside of bacteria determine whether it's virulent or nonvirulent.
B. A transforming principle in the S bacteria allowed the nonvirulent R strain to become virulent.
C. The translation of proteins, carbohydrates, lipids, and DNA is important in determining bacterial virulence.
D. The S-strain bacteria had not been killed completely.
Answer:
The correct answer is B.A transforming principle in the S bacteria allowed the nonvirulent R strain to become virulent.
Explanation:
In the transformation experiments, conducted by Fredrick Griffith in 1928, he observed that heat-killed S-strain bacteria injected into mice did not kill them. When he injected a mixture of heat-killed S and live R-bacteria, the mice died. He concluded that the R-strain bacteria had somehow been transformed by the heat-killed S-strain bacteria. This occurred perhaps due to absorption of some transforming principal or substance by rough type bacteria from heat killed smooth bacteria. It had enabled the R-strain to synthesize a smooth polysaccharide coat and become virulent. This must be due to the transfer of the genetic material. However, the biochemical nature of genetic material was defined not from his experiments.
Answer:
the correct answer is :
B. ( A transforming principle in the S bacteria allowed the nonvirulent R strain to become virulent.)
Explanation:
According to Griffith's experiment, he used two strains of (Streptococcus pneumoniae ) which is bacteria infect mice causing pneumonia.
First strain: type |||-S (Smooth) bacteria, this bacteria is virulent, it has the ability to kill mice because it covers itself with smooth polysaccharide capsule that resist the immune system of mice, and this ability is according to the genetic traits inside its DNA.
Second strain: type ||-R (Rough) bacteria, this bacteria is non-virulent, it doesn't have this protective capsule so the immune system can resist it and it can't kill the mice on their own.
Steps of experiment :
Griffith killed the |||-S. by heat The remains of killed |||-S where added to the ||-R. bacteria He injected the mice with this mixture of ( heat-killed |||-S and ||-R )Observation:
The mice all died, However the virulent |||-S strain bacteria killed by heat
Conclusion:
The DNA of the |||-S strain bacteria survived the heat and transformed to ||-R, this means somehow, type |||-S bacteria still alive inside the type ||-R.This process called transforming principle, that allowed the nonvirulent R strain to become virulent.Which if the following best describes why invertebrates isn’t considered a scientifically valid word when classifying animals
Answer:
I believe the answer is b.
Explanation:
All invertibrates share one charistic in common, they have no backbone.
Answer:
The correct answer is option D.
Explanation:
Invertebrates don’t have a common similarity in an anatomical structure that all have. They are different in their structure so they should not be grouped into one group.
All different groups of invertebrates have a different type of symmetry, composition, and anatomically different but there is not a common character except the fact that no one has vertebra.
Thus, the correct answer is option D.
Which of the following describes the difference in stimuli required to detect a difference between the stimuli?A. just noticeableB. signal detectionC. subliminalD. top down
Answer:
A. Just noticeable
Explanation:
examines our psychological experiences of physical stimuli. ... the just noticeable difference between two stimuli - the minimum amount of change required for a person to detect a difference. The louder or heavier or more of something that is occuring, the bigger the difference will need to be in order to detect it.
Animals have a variety of adaptations,including trachea and gills, which allow this key process to occur. Which provides the molecules necessary for cellular respiration and efficient ATP synthesis?
Answer:
Gas exchange
Explanation:
Trachea and gills are part of the respiratory system in organisms. These structures serve in gas exchange. The process of gas exchange removes carbon dioxide and allows oxygen gas to enter the body.
Aerobic cellular respiration is the efficient process of ATP synthesis as it produces the maximum number of ATPs by complete oxidation of nutrients. The process of aerobic cellular respiration needs the presence of oxygen.
Hence, Animals have a variety of adaptations, including trachea and gills, which allow gas exchange to occur. Gas exchange provides the oxygen necessary for cellular respiration and efficient ATP synthesis.
You need to connect your doorbell. You should select the wire that will a) accept the flow of electrons, b) resist the flow of electrons, c) accept the flow of protons, d) resist the flow of protons
30 POINTS!!!
if anyone knows the levels of classification for blue jays, robins, cardinals canaries and pelicans, YOUR HELP WOULD BE APPRECIATED!!
Answer:
Please refer to the attachments !!!
hope it helps !
The Blue Jay belongs to the animal kingdom (Animalia) and the phylum chordata (Chordata) since it is an animal with a spinal cord. The American Robin is also a member of the animal kingdom (Animalia) and the phylum chordata (Chordata).
Given that it is an animal with a spinal cord, the Blue Jay belongs to the phylum chordata (Chordata) and the animal kingdom (Animalia).
It belongs to the Aves class because it is a bird. The Blue Jay belongs to the Passeriformes order of birds, which also contains perching birds. It belongs to the Corvidae family, which includes the crows. Cyanocitta is the genus and cristata is the particular species.
The American Robin belongs to both the phylum chordata (Chordata) and the animal kingdom (Animalia). It belongs to the Aves class because it is a bird.
The order Passeriformes, which contains perching birds, includes the American Robin. It belongs to the Turdidae family, which includes thrushes. Turdus is the name of the genus, and migratorius is the particular species.
The Northern Cardinal is a member of the animal kingdom (Animalia) and the phylum chordata (Chordata), just like the other species. It belongs to the Aves class because it is a bird.
The Northern Cardinal belongs to the Passeriformes order, which is made up of perching birds. Cardinals make up their family, the Cardinalidae. Cardinalis is the name of the genus and the particular species.
The canary is a member of both the phylum chordata (Chordata) and the animal kingdom (Animalia). It belongs to the Aves class because it is a bird.
The order Passeriformes, which contains perching birds, includes the canary. It belongs to the Fringillidae family, which includes finches. Serinus is the name of the genus, and canaria is the particular species.
Despite not having a distinct species name, the pelican is a bird that belongs to the phylum chordata (Chordata) and animal kingdom (Animalia).
It belongs to the Aves class because it is a bird. The order Pelecaniformes, which includes pelicans and connected species, is where pelicans are categorised. Their genus name is Pelecanus, and they are members of the Pelecanidae family.
Thus, these classification assist scientists in organising and classifying various species in light of their evolutionary connections and similar traits.
For more details regarding classification, visit:
https://brainly.com/question/1620211
#SPJ4
What body systems are required when you are eating dinner? Explain how the systems work together.
Answer:
When you eat, the digestive and circulatory systems work together and increase the amount of nutrients in your body. As the nutrients are processed, your stomach sends signals to your brain to tell your body that you are full and to stop eating.
Explanation:
Gene expression is the process whereby genetic information in the cell is used to produce proteins. This is referred to as the central dogma. Match the descriptions of the components of gene expression with the correct terms.
A.The molecule that carries information from the DNA specifying a polypeptide to ribosomes.
B. The synthesis of an RNA copy of a gene.
C. The synthesis of a specific sequence of amino acids on a ribosome.
D. A molecule found in the nucleus of cell that contains the cell's genome.
E. A molecule made of amino acids that correspond to the genetic information in a structural gene.
DNA
TranscriptionmRNA
Polypeptide
Translation
Transcription is the creation of an RNA from a DNA template. The mRNA carries genetic information to ribosomes for translation, where a specific sequence of amino acids, forming a polypeptide, is constructed. The DNA in the nucleus of the cell holds the information for these processes.
Explanation:The process of gene expression involves several key steps and components:
Transcription refers to the synthesis of an RNA copy of a gene (B).mRNA, or messenger RNA, is the molecule that carries information from the DNA specifying a polypeptide to ribosomes (A).Translation is the synthesis of a sequence of amino acids on a ribosome based on the information conveyed by the mRNA (C).DNA is the molecule found in the nucleus of a cell containing the cell's genome. It is the blueprint for building the body's proteins (D).A Polypeptide is a molecule made of amino acids that correspond to the genetic information in a structural gene. These polypeptides fold into complex shapes to form proteins (E).Learn more about Gene Expression here:https://brainly.com/question/33276216
#SPJ6
If you repeat an experiment and the results are very different from the results you got the first time, the next step would be to
a. trust the second results.
b. try a different experiment.
c. decide which results are better.
d. repeat the experiment again.
Answer:
repeat the experiment again.
Answer:
repeat the experiment again
plzzz mark me the brainliest
Where does glycolysis take place in eukaryotic cells
Glycolysis takes place in the cytoplasm of nearly all living cells. It's an anaerobic process that breaks down glucose to extract energy for cellular metabolism. Glucose enters the cell through secondary active transport and facilitated diffusion via GLUT proteins.
Explanation:Glycolysis, which is the first step in the breakdown of glucose to extract energy for cellular metabolism, occurs in the cytoplasm of cells. This process is a key component of cellular metabolism in nearly all living organisms, including both prokaryotic and eukaryotic cells. Glycolysis does not use oxygen directly and is therefore termed anaerobic. In eukaryotic cells, the cytoplasm, the region outside the organelles but within the cell membrane, is where glycolysis occurs.
Glucose, which provides most of the energy for living cells, enters these cells in two main ways. One is via secondary active transport, which occurs against the glucose concentration gradient. The other involves a group of integral proteins known as GLUT proteins, or glucose transporter proteins. These transport proteins enable facilitated diffusion of glucose into the cells.
The near universal occurrence of glycolysis in life forms — from simple bacteria to complex human cells — hints that this biochemical process appeared early in the evolution of life and has been preserved due to its fundamental role in cellular energy production.
Learn more about Glycolysis in eukaryotic cells here:https://brainly.com/question/31811690
#SPJ12
Thyroid-stimulating hormone stimulates the thyroid gland to secrete sex hormones. true or false
Answer:
False
Explanation:
The thyroid gland cannot secrete sex hormones lol
There is a liquid capsule inside a cup full of liquid. The cup full of liquid has salt in it and the liquid capsule has no salt in it. In which direction will the solvent flow? A. The salt does not have to move B. From the capsule to the larger cup C. Equally between the capsule and the cup D. From the larger cup to the capsule
Because of permeation, the salt will flow equally between the capsule and the larger cup in its quantity.
Hope this helps!
Answer:
The correct answer will be option- D.
Explanation:
The movement of solute, as well as solvent particles, depends on the concentration gradient of solute particles. The permeability of the membrane allows the movement of solute particles from higher concentration to lower concentration through osmosis.
In the given question, the capsule contains low solute concentration while cup water contains high solute concentration. As the solute particles move from the low concentration (capsule) to high concentration (cup water) therefore the water will move from the cup water to the capsule.
Thus, option-D is the correct answer.
The part of the brain involved in controlling the body's overall reaction to stress is the
I think is the hypothalamus- pituitary-adrenal.
The function of the ciliary escalator is to
The ciliary escalator removes foreign particles and mucus from the respiratory system.
It is a respiratory tract process that aids in the removal of inhaled particles and mucus from the airways.
The ciliary escalator is made up of cilia, which are small hair-like structures that line the respiratory epithelium.
The cilia beat in unison, resulting in a wave-like action. Mucus, trapped particles, and bacteria are moved upward, away from the lungs, by this action.
Thus, by promoting the evacuation of undesirable particles and mucus, the ciliary escalator plays an important function in maintaining the cleanliness and health of the respiratory system.
For more details regarding respiratory system, visit:
https://brainly.com/question/4190530
#SPJ2
what are most genetic disorders that occur in humans?
A.polygenic
B.recessive
C.dominant
D.sex-linked
Answer:
d
Explanation:
what is a blastocyst
A. a sperm fused with an egg
B. a structure that nourishes the fetus
C. a ball of about 100 cells
D. an unfertilized egg
Answer: The answer is C
Explanation: it is the answer with 100 (apex)
A sperm fused with an egg is a blastocyst. Thus the correct option is A.
What is blastocyst?Three days after fertilization, a normally developing embryo contain about six to 10 cells. By the fifth or sixth day, the fertilized egg is known as a blastocyst (a rapidly dividing ball of cells).
The inner group of cells will become the embryo. The outer group will become the cells that nourish and protect it.
For more information regarding blastocyst, visit:
https://brainly.com/question/2013947
#SPJ2
To protect endangered species from becoming extinct, it’s highly recommended to raise the animals in protected areas such as zoos and wildlife sanctuaries. Although this step could protect them, what challenges do the animals face when these methods are used?
Zoos might help in protecting endangered species from extinction but trapping and keep them in unnatural environment is bad for their health as they limited space to roam around which leads to shorter life expectancy at times.
Challenges of animals in zoo :-Zoos are problematic from ethical point of view. Animals living in unnatural environment shows alteration in their behavior and such conditions may develop serious mental issues in them. Many times staff in wildlife sanctuaries aren't trained this leads to lack of individual treatment of animal. Most of the zoos doesn't really care about animals they use animals for profitable purposes. Zoos might not able to protect endangered species if the conditions are poor there too.
To learn about zoo challenges, refer here:
https://brainly.com/question/26618228
#SPJ2
Which of the following is a polygenic trait in humans?
A.attached ear lobes
B.height
C.widow's peak hairline
Answer:
B; height
Explanation:
Traits are polygenic when there is a wide variation in the trait.
The polygenic trait in humans is option B. height.
What is a polygenic trait in humans?Polygenic traits are traits that are controlled by multiple genes instead of just one. The genes that control them may be located near each other or even on separate chromosomes. Because multiple genes are involved, polygenic traits do not follow Mendel’s pattern of inheritance. Instead of being measured discretely, they are often represented as a range of continuous variation.Some examples of polygenic traits are height, skin color, eye color, and hair color.HeightHuman height is controlled by many genes, in fact, there are over 400 genes related to height, and all of these genes interact to make up a person’s phenotype. This is a very large number, but it makes sense because height is a compilation of the lengths of many different body parts, such as leg bones, the torso, and even the neck.To know more about Polygenic traits, refer to: https://brainly.com/question/12691060
#SPJ2
Sally was working in the kitchen when she was careless and picked up a hot pan with her bare hand. After healing, Sally continues to feel a loss of sensation on the lateral surface of her palm. Although Sally maintains normal movement in all her muscles, her cutaneous sensation has been impaired. Which nerve was most likely damaged as a result of her burning incident? View Available Hint(s) Sally was working in the kitchen when she was careless and picked up a hot pan with her bare hand. After healing, Sally continues to feel a loss of sensation on the lateral surface of her palm. Although Sally maintains normal movement in all her muscles, her cutaneous sensation has been impaired. Which nerve was most likely damaged as a result of her burning incident? Ulnar Radial Median Musculocutaneous Axillary
Answer:
The median nerve would be the most damaged nerve.
Where are many natural gas drill sites located?
Answer:
Explanation:
Did you mean the United States? If you did then Texas Oklahoma and California are the most likely places you would find Natural Gas. Natural Gas and Oil do go together and those states were where the major oil finds were.
In 1953, Miller and Urey constructed an experiment that attempted to mimic the conditions leading to the formation of biomolecules on early Earth.
Part A: Construct a hypothesis statement that Miller and Urey might have made prior to conducting their experiment. Use an “if, then” format to write your statement. (1 point)
Part B: Describe in detail their experiment. Include what they used to simulate the conditions of early Earth, and what their results were. (3 points)
Answer:
A// If early conditions of primeval earth had ammonia, methane, hydrogen in its atmosphere, then it is possible that amino acids such as glycine, α-alanine, and β-alanine may have been spontaneously formed from chemical reactions spurred by energy from lightning.
Their hypothesis was that the early conditions of primeval earth favored the spontaneous formation of organic molecules, from inorganic precursors, that may have been the origin of life. This theory is called abiogenesis.
B//Miller Urey put methane, ammonia, hydrogen gases in a glass flask and a pool of water at the bottom of the glass flask. The flask was heated moderately to simulate the hot conditions then. Sparks were also occasionally induced in the flask to mimic lighting. The flask was then cooled slowly to simulate cooling of earth over time.After one day, they found the presence of some amino acids (glycine, α-alanine and β-alanine) was discovered in the water in the flask
Explanation:
^
Answer:
part a:If early conditions of primeval earth had ammonia, methane, hydrogen in its atmosphere, then it is possible that amino acids such as glycine, α-alanine, and β-alanine may have been spontaneously formed from chemical reactions spurred by energy from lightning.
Their hypothesis was that the early conditions of primeval earth favored the spontaneous formation of organic molecules, from inorganic precursors, that may have been the origin of life. This theory is called abiogenesis.
part b:Miller Urey put methane, ammonia, hydrogen gases in a glass flask and a pool of water at the bottom of the glass flask. The flask was heated moderately to simulate the hot conditions then. Sparks were also occasionally induced in the flask to mimic lighting. The flask was then cooled slowly to simulate cooling of earth over time.After one day, they found the presence of some amino acids (glycine, α-alanine and β-alanine) was discovered in the water in the flask
Explanation:
PLEASE HELP! Dolphins and porpoises are closely related species. Name three pieces of evidence for evolution you could look at that would support this claim:
Answer:
Both the porpoise and dolphins are categorized in similar mammalian order Cetacea. Both exhibit streamlined body, their hindlimbs are vestigial, forelimbs got modified into flippers, and both primarily eat fish.
The porpoises and dolphins are evolutionarily closely associated as both are toothed whales, in comparison to another group of Baleen whales. All the individuals of Cetacea are the progenies of terrestrial ungulates. The primitive ancestors first originated into the sea about fifty million years ago, and about 35 million years ago, there took a partition in the two distinct lines, of these the toothed whales established a strong sense of echolocation.
Answer:
They have very similar anatomy.