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?

Astudent reads the following text in a science book: scientific evidence tells us that the cause of earths four seasons is the tilt of earth as it revolves around the sound the student is instructed to illustrate this information in a science book. how will the student illustrate winter in the northern hemisphere? a.earths northern hemisphere will tilt away from the sun. b. earths northern hemisphere will tilt toward the sun. c.earths orbit will be farther away than from the sun d. earths southern hemisphere will tilt away from the sun.

Whats one way that rocks do not follow the typical rock cycle pathway?

What is a photon? a. part of a ribosome b. a light particle c. a carbon dioxide molecule d. part of a chloroplast b.a light particle