Question

although not yet aware of her pregnancy, mrs. enriquez has conceived a single cell from the union of an egg cell and a sperm cell. this single cell is called a(n):
baby.
embryo.
fetus.
zygote.

Explanation:

When an egg cell and a sperm cell unite, they form a zygote. A baby is a fully - developed human offspring after birth. An embryo is the early stage of development after the zygote has started to divide (usually from about 2 - 8 weeks of gestation). A fetus is the stage of development from about 9 weeks of gestation until birth. The single cell formed by the union of egg and sperm is specifically called a zygote.

Answer:

zygote.