Prokaryotic cells have a nuclear while eukaryotic cells have a nucleus. Eukaryotes have membrane bound organelles. Eukaryotes have chromosomes while prokaryotes do not. Also prokaryotic cells have circular DNA while eukaryotic cells have linear DNA, or "double helix".
Answer:
Damage to DNA can render a cell useless, or even harmful to an organism. Apoptosis, or programmed cell death, evolved as a rapid and irreversible process to efficiently eliminate dysfunctional cells. A hallmark of cancer is the ability of malignant cells to evade apoptosis.
Explanation:
Answer:
You can't see the blood vessels themselves because vision depends on a process that makes it impossible to see things that are stationary with respect to the retina. Light receptors in the retina respond only to changes in light reaching them, not to a steady image.
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