17. When two or more elements combine chemically, they form .

an element

a compound

an atom

a lipid

During the day, plants produce by splitting water molecules in the light-dependent reactions of photosynthesis. at the same time, plants use cellular respiration to produce some of the needed by the light-independent reactions to make sugars. during the night, plants produce because takes place.

How do living things obtain phosphorus

Which statement explains how gravity and intertia work together