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.
A fish swims with it's fins and breathes under water with it's gills.
Answer:
b.Movement of phospholipids in the plasma membrane from one monolayer to the other requires the polar or charged head groupd to enter the hydrophobic interior of the lipid bilayer. This process requires a large positive change in free-energy, thus making this type of movement unlikely without an input of energy
The plasma membrane serves a protective function for the cell and is a selective membrane for particles entry
Both have a pump that pushes materials throughout the organism.
