Q: What makes up most of biological tissues? Choices: - air - muscle - bone - water A:
water

Q: What often occurs on steep slopes in dry climates? Choices: - volcanoes - earthquakes - tsunamis - landslides A:
landslides

Q: What monitors the level of carbon dioxide in the blood? Choices: - the lungs - the heart - the kidneys - the brain stem A:
the brain stem