*Question*
Q: Cellular respiration and photosynthesis are important parts of which cycle? Choices: - vapor cycle - greenhouse effect - water cycle - carbon cycle A:
**Answer**
carbon cycle

*Question*
Q: The fact that all animals have certain traits in common shows that they share what? Choices: - a common gene - a common brain - a common planet - a common ancestor A:
**Answer**
a common ancestor

*Question*
Q: What are surface currents mainly caused by? Choices: - lightning - waves - rains - winds A:
**Answer**
winds

*Question*
Q: How many valves are in the heart? Choices: - one - six - two - four A:
**Answer**
four