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.
<span>amylase is an example of an enzyme</span>
In biochemical reactions, it is mostly triggered by enzymes. Enzymes are important components in the process that involves metabolism and digestive functions, further, most of these enzymes are proteins.Proteins are biological macromolecule and mostly composed of enzymes. Proteins play a role in the physical make-up of a cell or acts as a cytoskeleton –maintains cell shape and figure. These proteins plays different roles and works with nucleic acids and other macromolecules in the cells including cell cycle, cell adhesion, immune response and cell indicators.
Plant cells do not perform respiration, so A,C, and D couldn't be correct but they don't digest either. so gain energy plants go through a light dependent reaction and the Calvin cycle which makes up photosynthesis.
The mechanisms of reproductive isolation prevent the reproduction of two individuals from different species. The prezygotic mechanisms disrupt the stages of reproduction before the forming of the zygote or prevent the mating at the start, and the postzygotic mechanisms affect the stages of reproduction after the forming of the zygote.
So, the first and the third example (the urchins and the grasshoppers) show the prezygotic mechanism, as the two individuals are not able to mate or form a zygote.
The second and the fourth example ( zonkey and the death of a zygote) show the working of the postzygotic mechanisms, as the zygote is formed, but it seems to be inviable, and the zonkeys are sterile, preventing the individual to reproduce.
