Q: Q: Most of the heat that enters the mesosphere comes from where? A: | OPTIONS:
- Earth's surface
- Exosphere
- Troposphere
- the stratosphere
A: the stratosphere

Q: Q: What do herbivores eat? A: | OPTIONS:
- minerals
- meat and plants
- animals
- plants
A: plants

Q: Q: The primary hormones derived from lipids are what? A: | OPTIONS:
- amino acids
- melatonins
- antibiotics
- steroids
A: steroids

Q: Q: All atoms have equal numbers of what two particles? A: | OPTIONS:
- nuclei and neutrons
- photons and protons
- electrons and neutrons
- electrons and protons
A: electrons and protons