Which factors were determined to directly cause the loss of skin pigmentation in humans as a result of natural selection? (1 point)

1. a change in the diet of human populations as they settled in colder climates

2. the clothing worn by humans in the early 8th century

3.the interaction of human populations with predators in colder climates

4.the impact of UV radiation on folate and Vitamin D levels in human populations

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?