I think the answer is a. Eclipse. Hope this helps . :)
The answer to finish this sentence would be ''the amount of genetic variation in a population'' because environmental factors can either increase or decrease a population.
Answer:
Pheromones
Explanation:
Pheromones play an important role in the behavioral isolation of insect species. These compounds serve to identify individuals of the same species and of the same or different sex. Evaporated molecules of volatile pheromones can serve as a wide-reaching chemical signal. In other cases, pheromones may be detected only at a short distance or by contact.
