Problem:OPTIONS:
- animals
- tanks
- an organism's body
- living things
- hydrogen
- space
- Veins and arteries.
- mammals

Fact 1: Cells cannot survive without oxygen. Fact 2: Cells are the units of function in living things. Given the two facts above, what cannot survive without oxygen?
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A: living things

Problem:OPTIONS:
- no mammals
- all mammals
- dogs
- animals
- honeybees
- insects
- some mammals
- alpacas

Fact 1: Platypus females lay their eggs in a burrow. Fact 2: Like the platypus, it is an egg laying mammal. Given the two facts above, what lays their eggs in a burrow?
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A: some mammals

Problem:OPTIONS:
- rocks
- some mammals
- Frogs
- monotremes
- humans
- bacteria
- elephants
- oak trees

Fact 1: Lungs are used for breathing air by land animals. Fact 2: Elephants are the largest animals on land. Given the two facts above, what uses lungs for breathing air?
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A: elephants

Problem:OPTIONS:
- HIV
- lack
- DDT
- p53
- antibiotics
- h2o
- memory cells
- HPV

Fact 1: Immunodeficiency occurs when the immune system is not working properly. Fact 2: HIV, the human immunodeficiency virus, is a retrovirus. Given the two facts above, what causes the immune system to not work properly?
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A:
HIV