Controls the movement of substances in and out of cells and organelles.
they keep toxic substances out of the cell; also they contain receptors they also channels that allow specific molecules, such as ions, nutrients, wastes, and metabolic products, that mediate cellular and extracellular activities to pass
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Answer:
it is clearly the oxygen cycle
Answer:
A nucleotide consists of a sugar molecule (either ribose in RNA or deoxyribose in DNA) attached to a phosphate group and a nitrogen-containing base. The bases used in DNA are adenine (A), cytosine (C), guanine (G), and thymine (T). In RNA, the base uracil (U) takes the place of thymine.
Explanation:
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Nitrogen because it is essential for making nucleic acids and amino acids in plants. Nucleic acids make DNA and RNA and amino acids make proteins. All are needed for cell growth and repair.