Cell membranes (plasma membranes) organisms maintain homeostasis by controlling what substances may enter or leave cells. some substances can cross a cell membrane through passive transport, while other substances can only cross a cell membrane through active transport. what is the difference between active and passive cellular transport?

How does secondary succession differ from primary succession?

What is the difference between a scientific hypotheses and a scientific theory?

Water changes bacteria in the soil converts this nutrient into a usable form. plants take up the usable nutrient through the soil and assimilate it into proteins, making it part of the plant. an animal eats the plants, and the nutrient becomes part of the animal. when the animal dies, it decomposes, returning the nutrient back to the soil. which cycle is being described? water cycle carbon cycle nitrogen cycle phosphorous cycle