Choose the best description for the prokaryotic cells.

has a nucleus; found in multicellular organisms
has no nucleus; found in unicellular organisms
has no nucleus; found in multicellular organisms
has a nucleus; found in unicellular organisms

How is the male reproductive system different from other body systems? it isn’t necessary to vital signs. it monitors other body systems, and adjusts if necessary. it transports items from one system to another. it is the only system that produces hormones in the male.

What causes darkening of the skin as melanin production increases

These are the components of the reservoirs of carbon that are exchanged in our environment.