The theory says that all living things are composed of cells. it also says that cells are the basic units of structure and function in living things and that new cells come from existing cells. a. evolution b. boveri–sutton chromosome c. genetic determinism d. cell

D. cell

Explanation:

The cell theory suggested three proposed statements those were all living things are composed of cells, the cell is the smallest entity of life and all cells formed from the pre-existing cells. This discovery is attributed to Robert Hook, who first began the study of cells in his self constructed microscope. But two scientists named as Matthias Schleiden and Theodor Schwann were the contributors of this theory in 1839.

before, trains worked using the steam engine. thus, it uses heat so it is crucial to apply heat balance. the steam engine absorbs energy during the stage of boiling water. so, this is the endothermic reaction. when the steam is used to work the piston, it has to release this energy through running the train. the excess energy is released as an exhaust to the chimney. this is the exothermic process because it releases energy to the surroundings.