They use them as food and habitats.
omnivore⇒herbivore⇒autotroph
this is because an autotroph makes its own food (photosynthesis) so it doesn't have the need to eat other organisms. Herbivores eat only plans (remember this with the word herb is a type of plant) and an omnivore will eat either meat or plants so it can eat either of the things below it.
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