I think the third statement is correct. RNA consist of ribose sugar while DNA consist deoxyribose sugar. and the nitrogenous base that is different would be the thymine in DNA becomes a uracil in the RNA
The central nervous system has two functions. One, where the brain is, is to be the center of thoughts and the interpreter of outside influences, while the spinal cord connects all parts of the body with the brain.
The mass of a tree is primarily carbon. The carbon comes from carbon dioxide used during photosynthesis. During photosynthesis, plants convert the sun's energy into chemical energy which is captured within the bonds of carbon molecules built from atmospheric carbon dioxide and water.
Starch (a polymer in glucose)
I'd mark answer B :) technically it means that you must eat enough food rich in those aminoacids because they can't be synthesized by the organism.
