A. Immune system
It helps our bodies fight everything that comes in our path.
<span>The environment has a greater amount of long nectar tubed flowers and short nectar tubed flowers causing disruptive selection in medium bill length birds.
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The answer is C. The Scientific Method is the method used whenever you want to explain or figure out anything scientifically. It involves hypothesis, experiments, and conclusions
I believe the answer is D) all cells are produced from other cells
