AP BIOLOGY

Detailed explanation-1: -Sexual reproduction starts with the combination of a sperm and an egg in a process called fertilization. This can occur either inside (internal fertilization) or outside ( external fertilization) the body of the female. Humans provide an example of the former whereas seahorse reproduction is an example of the latter.

Detailed explanation-2: -Fertilization in humans is internal. The male introduces the sperms into the female reproductive tract. The sperm fuses with the egg in the ampulla of the fallopian tube. This results in the formation of a zygote which undergoes mitosis to form an embryo.

Detailed explanation-3: -There are two different types of fertilization-internal fertilization, where the fusion of egg and sperm occurs inside the female reproductive tract, for eg., humans; and external fertilization, where the fusion of male and female gametes occurs outside the body of the organism, for eg., sea urchins, frogs, etc.

Detailed explanation-4: -Human reproduction naturally takes place as internal fertilization by sexual intercourse.