LIFE SCIENCE

Detailed explanation-1: -Sexual reproduction results in offspring that are genetically unique. Each human couple has the potential to produce more than 64 trillion genetically unique children. Together with random fertilization, more possibilities for genetic variation exist between any two people than the number of individuals alive today.

Detailed explanation-2: -There are 8, 324, 608 possible combinations of 23 chromosome pairs. As a result, two gametes virtually never have exactly the same combination of chromosomes. Each chromosome contains dozens to thousands of different genes.

Detailed explanation-3: -Since chromosomes assort independently, maternal and paternal chromosomes can combine in 2 to the 3rd power, or 8, ways to create gametes. Humans have 23 pairs of chromosomes, so each person can produce 2 to the 23rd power, or 8.4 million, different kinds of gametes!

Detailed explanation-4: -A sperm cell, with over 8 million chromosome combinations, fertilizes an egg cell, which also has over 8 million chromosome combinations. That is over 64 trillion unique combinations, not counting the unique combinations produced by crossing-over.