Answer:
There is no control group and variables were not addressed.
Explanation:
In the context, it is given that there is a dumping ground in a small town called Love Canal and harmful chemical waste of industries are dumped there. Lately, it is noticed that there were traces of the toxic substances on the walls of the schools and the hospitals. The hospitals also noticed that during the period of 1970 to 1980, there were increase in the number of the birth defects in the area. The people of the Love Canal has genetic abnormalities and the chemical waste is responsible for it.
Thus it can be concluded that there is a no such any control group in this case. The confounding variables like the comorbidities as well as the family history of the genetic defects were not addressed.
Well the first difference is that PMS is mostly a psychological and somewhat physical syndrome. The proof is that the symptoms of PMS are irritability, stress and dysphoria. There is of course a lot of other symptoms like anxiety, insomnia, headache, fatigue, mood swings, and increased emotional sensitivity. The cause of PMS are the changes in levels of estrogen and progesterone. Now, menstrual cramps are physical condition. The symptom is pain in lower abdomen. And the cause is the menstruation itself. So there you have the differences. PMS as its own name says (Premenstrual syndrome) occurs before menstruation, more accurately 5 - 10 days before menstruation which is luteal phase of menstrual cycle. Menstrual cramps can occur several days before menstruation or can occur when menstruation starts, and they slowly disappear as menstruation slowly ends
The answer would be D, Schwann cells, because they are a part of the myelin sheath (which covers the neurons). c:
