What are the three processes in meiosis that ensure variety in sexually reproducing organisms?

Melting glaciers is a serious threat to the environment what is the possible consequence of melting glaciers on polar bears?

During which phase does earth see more than half of the moon's surface? 1)first quarter2)third quarter3)waxing gibbous4)waning crescent

Acell in the human nervous system whose primary function is to form myelin and the blood-brain barrier, respond to injury, remove debris, and enhance learning and memory is called a(n) cell.