Which of the following uses a protein to move a molecule across a cell membrane without energy?
O A. Active transport
OB. Facilitated diffusion
O c. Simple diffusion
OD. Osmotic pressure

Legumes, a type of plant, require rhizobia, a type of soil bacteria, to survive since these organisms fix nitrogen during photosynthesis. rhizobia use the legumes for food. what would most likely happen to the legume population if rhizobia suddenly became extinct?

Describe the structure of a virus, and explain how this structure differs from that of a cell.

What two atoms form a covalent bond a.a sodium and chlorine atom b. an iron and oxygen atom c. two oxygen atoms d. two sodium atoms apex