<span>Every living organism begins life as a single cell. Unicellular organisms may stay as one cell but they grow too. Multicellular organisms add more and more cells to form more tissues and organs as they grow. </span>
With the beginning of the middle proterozoic comes the first evidence of oxgen build up in the atmosphere. with is catastrophe came eukaryotic forms. these include multicellular algae, and toward the end of the proterozoic the first animals
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I honestly know its B cause I had the same question asked by my teacher
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In animal field studies, why do scientists usually try to work without making the animals aware that the humans are present? It is necessary to observe the animals without disturbing them. When a controlled experiment is not possible, why do scientists try to identify as many relevant variables as possible?
