Question

what hormone causes the endometrial lining to thicken?
testosterone
lh
fsh
estrogen

Explanation:

Testosterone is a male sex hormone with no role in endometrial thickening. LH (Luteinizing Hormone) triggers ovulation, while FSH (Follicle-Stimulating Hormone) stimulates follicle development in the ovaries. Estrogen, produced by developing ovarian follicles, directly promotes the thickening of the uterine endometrial lining during the follicular phase of the menstrual cycle.

Answer:

Estrogen