Next, Mendel took the F1 progeny and allowed them to self-fertilize. In the resulting F2 generation, 3/4 showed the dominant phenotype, and 1/4 showed the recessive phenotype. ... 1 out of 3 round pea plants from the F2 generation were true-breeding and produced only offspring with round peas.
I think that the answer is 12 billion. So sorry if I am not right.
Here are the answers in chronological order:
1.28
2.ovaries
3. Fallopian tube
4. ovaries
5. ovary/ovum
6.ovary/ovum
7. ovulation
8. egg
9. uterus
10. vascular endometrial tissue
11. Fallopian tube
12. sperm cell
13. uterus
14. fertilized
15.blood
16. uterine
17. cervix and vagina
18. 28
19. menstruation
The answer is (D) convergent