Question

1. which hormone causes the endometrial layer inside the uterus to thicken?

testosterone
estrogen
progesterone

Explanation:

Estrogen plays a key role in the menstrual cycle. During the follicular phase of the menstrual cycle, estrogen is produced by the growing follicles in the ovary. It causes the endometrial layer (the inner lining of the uterus) to thicken. This thickening is to prepare the uterus for potential implantation of a fertilized egg. Testosterone is a male - sex hormone (though females have small amounts) and is not directly involved in endometrial thickening. Progesterone, which is produced after ovulation (in the luteal phase), further modifies the endometrium (making it more suitable for implantation if pregnancy occurs), but the initial thickening is mainly due to estrogen.

Answer:

B. estrogen