Why do sex cells(sperm and egg) need to have half the number of the organisms chromosomes

Sex cells contain only half of the hereditary material present in the body cells that form them. This is important because male and female sex cells ultimately join to become a fertilized egg, which gives rise to a new organism, or offspring.

clumped distribution, because you'de have all of the population gathered in a relatively small are.

it's the most common because it provides protection and a mate for reproduction

example: humans, seeweed, cattles, etc.

correct answer is a. and d.