I believe a. is the answer
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Answer:
Girls have menstrual cycles because girls have changes of hormones in their body. The hormones make the lining of the uterus build up. This gets the uterus ready for an egg which when the egg is released it causes a period also known as a menstrual cycle which happens normally every month for at least 3-7 days.
Explanation:
The answer to your problem is c
