Final answer:
PMS symptoms are primarily caused by fluctuations in hormone levels, particularly the changes in progesterone and estrogen during the luteal phase of the menstrual cycle. Option d.
Step-by-step explanation:
Symptoms associated with PMS (Premenstrual Syndrome) are probably caused by fluctuations in hormone levels. PMS encompasses a range of physical and psychological symptoms that typically occur in the luteal phase of the menstrual cycle which follows ovulation. This phase involves hormonal changes, including the rise and fall of progesterone and estrogen. These hormonal changes can cause a variety of symptoms such as mood swings, abdominal bloating, breast tenderness, and acne. The concept that hormone fluctuations can impact physical and mental well-being is central to understanding the etiology of PMS.
It is throughout the luteal phase that progesterone levels initially increase and then decrease as the corpus luteum degrades, leading to the shedding of the endometrium if pregnancy does not occur. This hormonal decline is a key event that sets the stage for menstruation and can influence premenstrual symptoms. Thus, hormonal fluctuations, rather than ovulation, thickening of the uterine lining, or body temperature changes, are primarily associated with the manifestation of PMS symptoms.