Fact 1: Cells cannot survive without oxygen. Fact 2: Air contains oxygen. Given the two facts above, answer the question "What helps cells survive?" with the following options: - DNA - all copper - air - space - RNA - coat - heat - gasoline
air

Fact 1: Cutting down trees has a negative impact on an ecosystem. Fact 2: If trees are cut or burned, the carbon is released back into the atmosphere. Given the two facts above, answer the question "Releasing what can have a negative impact on an ecosystem?" with the following options: - disease - viruses - A virus - Carbon - tar - toxins - herbicide - vehicles
Carbon

Fact 1: Nephrons are the structural and functional units of the kidneys. Fact 2: Nephrons consist of vascular and tubular components. Given the two facts above, answer the question "the structural and functional units of the kidneys consist of vascular and tubular what?" with the following options: - Epidermis - organ - epidermal - it needs them - critical organs - sensory neurons - components - Joules
components