biological clock
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Tweet n. 1. An internal mechanism in organisms that controls the periodicity of various functions or activities, such as metabolic changes, sleep cycles, or photosynthesis. 2. a. The time period during which a person who desires to have a biological child, especially a woman approaching the decline of reproductive capability, is still able to do so. b. The capacity to be fertile, especially in such a woman: She was eager to have a child before her biological clock stopped working. |
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