input: OPTIONS:
- gravity
- uteris
- ovaries
- lack of fertilization Now, answer this question: Q: What causes the menstrual cycle to be repeated? A:
A:
output: lack of fertilization

Q: Osteoclasts break down bone to maintain mineral what? A:

OPTIONS:
- density
- fluctuations
- polarity
- homeostatis

Answer: homeostatis

Problem: OPTIONS:
- excretory
- respiratory
- neither
- both
Q: Q: Are the lungs organs of the excretory system, the respiratory system, or both? A:
Answer: both

Problem:OPTIONS:
- fossil fuels
- oxygen
- greenhouse gas
- atmosphere

Q: What supports life, and is also needed for the water cycle and weather? A:
****
A: atmosphere

Q: Where does fertilization usually take place? A:
OPTIONS:
- uterus
- ovary
- vagina
- fallopian tubes
fallopian tubes

Q: Microevolution occuring and taking place over many generations results in? A:
OPTIONS:
- fission
- microinjection
- recalibration
- macroevolution

Answer:
macroevolution