The majority of cases of blindness are caused by _____, and are treatable

What happens that determines the sex of the offspring?

a. The eggs or ovum contain the X chromosome and the sperm cells carry either the X or the Y. The sperm cell that is involved in fertilization determines the sex of the offspring. b. The sperm cells all carry the X chromosome. The ovum contains both the X and Y, so it is the ovum that determines the sex of the offspring. c. The ovum and sperm cells both carry X chromosomes. The placenta carries both the X and Y and it determines the sex of the offspring. d. The ovum and the sperm cells both contain the X chromosome. During the course of fertilization either an X or a Y will be created, which determines the sex of the offspring.

An inherited characteristic that, through natural selection, increases in a population because it helps to solve a survival problem at the time it emerges is called

a. an adaptation. b. a genetic mutation. c. a dominant gene. d. a homozygous pairing.