Please help me solve this question

Which of the fallowing best completes the sequence 12,8,5, a) 1 b) 2 c)4 d)0

Suppose a man is heterozygous for heterochromia, an autosomal dominant disorder which causes two different‑colored eyes in an individual, produced 25‑offspring with his normal‑eyed wife. of their children, 15 were heterochromatic and 10 were‑normal. calculate the chi‑square value for this observation.

What are different types of statistical programs