Molecules entering an organism that has no physiological function and is not found in an organism if not taken up by eating, breathing, or injury. The term xenobiotics is used to describe a foreign particle or molecule that is potentially dangerous or toxic.
A zygote is a fertilized egg containing two sets of chromosomes, one from the egg (oocyte) and one form the sperm. The zygote is a single cell and the result of a fusion between two gametes, an egg (female) and one sperm cell (male).
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