This essential gas is important so that we can breath what is it ?

How can scientists test their ideas about the origin of the universe if they can't physically interact with or study?

Discuss the functions of epithelial connective nerviud and muscular tissues

Once an egg cell is fertilized by sperm, the cell then, as the embryo develops, it receives nourishment and eliminates wastes by transferring substances from its blood to its mother's blood. a. becomes a fetus immediately and exits the womb b. begins to divide and implants itself in the wall of the uterus c. remains in the uterus without dividing for several months d. travels back to the ovaries until the fetus is developed