Ascientist is comparing the outer layer of an onion cell to the outer layer of a human skin cell. what is unique about the outer layer of the onion cell compared to the skin cell?
a. it contains proteins.
b. it contains cellulose.
c. it contains carbohydrates.
d. it is selectively permeable.

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.