Answer: The correct answer would be gene pool.
Explanation:
Gene pool refers to the sum of all the alleles in an individual.
The allele refers to the alternate forms of the gene.
Large population usually has more genetic diversity as compared to small population. Variation in gene pool is essential for survival of a population.
D) laboratory experiments because every experiment needs a control and a variable.
Explanation:
Oxygen is the answer. (option B)
