Answer is A. A population becomes separated by environmental factors into two groups that do not reproduce with one another.
When a population of a species become geographically separated then gene flow between them stops. Over a period of time, the population may become genetically different in response to the natural selection due to different environments. Selection and genetic drift will act differently on these two separated populations. This will results into two separate species. This type of speciation is called allopatric speciation.
The polar head of a phospholipid is made of phosphate. The polar head has a negative charge that is made up of phosphate molecules. This polar region attracts water and is positioned outward to interact with the water.
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Answer:Muscle cells are able to produce ATP with oxygen, which is called aerobic respiration, or without oxygen, an anaerobic process called anaerobic glycolysis or fermentation. The process in which ATP is made is dependent on the availability of oxygen (see the Cellular Respiration concepts).
Explanation:
Answer: They compare the number of mutations to determine how long ago species separated and evolved.
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Endocytosis and exocytosis are similar in that they are both forms of cell transport. They differ because in endocytosis, a cell transports molecules into a cell (think: endo - in), and in exocytosis, the cell's molecules are transported by being expelled.