Definition: A thin, flexible, semipermeable barrier around the cell which regulates what enters and leaves the cell.

Explain why ecosystem diversity results in species diversity in a healthy biosphere

Describe how a non-resistant staphylococcus aureus bacterium can produce a bacterium that is resistant to methicillin

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