What is the source of estrogen and progesterone during the first ten weeks of pregnancy?
a. ovarian follicle
b. placenta
c. corpus luteum of pregnancy
d. anterior pituitary
e. trophoblast
C
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The primary stimulus for erythropoietin secretion is decreased iron concentrations in the liver.
Answer the following statement true (T) or false (F)
In this figure showing an anterior view of the heart, the left atrium is noted by number
A. 1. B. 2. C. 3. D. 4. E. 5.
Which of the following statements about blood is false?
A) It contains buffers that control pH. B) Normal pH is 6.8 to 7.0. C) It is more viscous than water. D) It is about 55 percent plasma. E) None of the statements are false; all are true.
Which of the following is the second step in the process of fertilization?
A. The sperm nucleus enters the egg, and the egg immediately prevents any further sperm from gaining access by forming a fertilization membrane that a sperm cannot penetrate. B. A sperm fuses with the egg's plasma membrane. C. The capacitated sperm release their acrosomal enzymes to penetrate through the cells surrounding the egg. D. The nuclei of the sperm and egg rupture within the fertilized egg and the chromosomes mix to form a single nucleus.