Can a catalyst be used over and over again?

Describe the function of the endomembrane system? what organelles are involved?

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

The law of thermodynamics states that energy can't be created or destroyed. to natural sources of energy on earth are the