A Scientist wonders if the amount of Vitamin C that he feeds to rats will have any affect on the rats' mass. He measured both the mass of the rats and the amount of Vitamin C in grams. Identify the controlled variable.
Plsss its due in 15 mins

Astructure that is found in a plant cell and not in an animal cell is a ? central vacuole mitochondrion nucleus ribosome

This is a typical grassland food web. it is also a small picture of an important cycle on earth: the carbon cycle. describe how the carbon gets into this food web. a) bacteria and fungi, the decomposers, recycle carbon from dead organisms. b) carbon is found in the grass and is passed from one level to the next in this food web. eliminate c) all living things give off carbon dioxide as a by-product of respiration and it is released into the atmosphere. d) plants use carbon dioxide as a reactant in photosynthesis, to make usable chemical energy in the form of a sugar.

About how many years does it take for one cycle of surface water to become deep water and then surface water again in the oceans? 101001,000