Which of the following is an example of a closed system?
an estuary where fresh and ocean water mix
a chemical reaction within deep ocean organisms allowing them to glow
a living single-celled organism such as a phytoplankton
a river that flows into the ocean

According to the cell theory, which describes cells? a. all organisms are composed of multiple cells. b. all cells have the same structure and function. c. cells are found in everything on earth. d. living organisms are not created spontaneously

5. what might happen if you were to remove all light from the setup after the discs have all become buoyant? describe what you would see. explain why this would occur with relation to cellular processes like respiration. [referring to an ap biology lab in which spinach discs are placed in a sodium bicarbonate solution and exposed to light.]

30 points why do tornadoes happen more frequently in the summer? they require warm air. they form over large, warm bodies of water. they require dry air. they require dust which is present in the summer.