Each cell has an outer covering called the ________, which allows some substances passage into or out of the cell and denies passage to other substances.

Performing ________ is the number one way to prevent spreading infections

a. fast surgery b. hand hygiene c. with sterile gauze d. with disinfectant

In the human life cycle, the fertilized egg is called a ________

A) fetus B) embryo C) zygote D) gonad