Why does each person have the same genetic makeup as the zygote they developed from

Which pattern most likely came from a gunshot and which one was produced from a blow on the head? explain your answer?

6. in domesticated cats, the following are independently assorting: normal ears (t) is dominant to tufted ears (t); curved whiskers (c) is dominant to straight whiskers (c); the presence of six toes (s) is dominant to five toes (s); gene for hair length is an x-linked codominant. the three phenotypes for hair length are long (xhxh), medium (xhxh), and short (xhxh); medium is the heterozygous condition. given two parents: ttccssxhxh x ttccssxhy how many different gametes could be formed in the female cat with respect to these four traits? how many phenotypes are possible in the offspring from this mating?

Which enzyme is responsible for “unzipping" the dna by breaking the hydrogen bonds between the nucleotides?