This is referring to meiosis, which happens just once to make reproductive cells, unlike mitosis which is just simple copying.
In mitosis, one cell splits into two, but the number of chromosomes doesn't change. The original cell makes two copies of its chromosomes and divides them up.

In <em>meiosis</em>, however, our cell doesn't bother making those two copies. It just takes what it has and divides it between two new cells.
The term metabolism would refer to the chemical reactions that involve the acquisition, storage, or release of energy within cells. It is all the processes involved that would maintain life of organisms. It is divided into catabolism (breaking down of molecules) and anabolism (synthesis of the compounds needed for catabolism).
Answer:
D.) Gene Flow
Explanation: In a population genetics, gene flow (also known as gene migration or allele flow) is the transfer of genetic material from one population to another. If the rate of gene flow is high enough, then two populations will have equivalent allele frequencies and therefore can be considered a single effective population.