Q: Most of the trash in the ocean is made of what material? Choices: - styrofoam - hydrocarbons - wood - plastic A:
plastic

Q: Bones consist of four types of tissue, compact bone, spongy bone, bone marrow, and what? Choices: - collagen - epithelium - plasma - periosteum A:
periosteum

Q: What causes lightning during a thunderstorm? Choices: - difference in wind - difference in elevation - difference in temperature - difference in charge A:
difference in charge