Question

humans possess two alleles, or variations, for each gene. the alleles may be the same, or they may be different. when humans reproduce, their alleles are separated and independently sorted into different gametes, or sex cells. so, when sex cells randomly combine during fertilization to produce offspring, there is
○ a. a low probability of survival
○ b. a high probability of producing a clone
○ c. a decreased risk of mutation
○ d. an increase in genetic variation

Explanation:

题目描述了人类每个基因有两个等位基因，繁殖时等位基因分离并随机组合到不同配子中，受精时细胞随机结合。这一过程会增加遗传变异。

• 选项A：文中未提及生存概率低，与题意无关。
• 选项B：产生克隆的概率高不符合基因随机组合的情况。
• 选项C：文中未提及突变风险降低。
• 选项D：等位基因分离、配子随机结合会增加遗传变异，符合遗传学原理。

Answer:

D. an increase in genetic variation