The letter b will be your answer
It enters the heart via the pulmonary veins
I believe the answer would be d.muscle cramps. Breathing in toxins seems like it could relate to the other three answers.
Answer:
The answer is Estradiol; LH and FSH; progesterone
Explanation:
during the menstrual cycle, Estradiol peaks first, LH and FSH peak next, and finally progesterone peaks.