Fact 1: Antibodies are large, Y-shaped proteins that recognize and bind to antigens. Fact 2: Allergic reactions are caused by substances called antigens. Given the two facts above, allergic reactions can be caused by?
OPTIONS:
- animals
- smoking pipes
- Sulfur dioxide
- Chemical energy
- fur and fat
- antibodies
- smoking tobacco
- Pesticides

Answer: antibodies

Fact 1: When an electrical circuit is working properly , electrical current runs through that circuit. Fact 2: An electric current is then used to burn the tumor away. Given the two facts above, when the electrical circuit is working properly, what can happen?
OPTIONS:
- dogs can run
- heat production
- enormous damage to homes
- a tumor can be burned away
- massive damage
- sperm and egg fuse
- baskets can be hand-woven
- bacteria can thrive

Answer: a tumor can be burned away

Fact 1: Reproduction is the process by which organisms give rise to offspring. Fact 2: Mutations are sources of variations in offspring. Given the two facts above, what can happen during the reproduction process?
OPTIONS:
- tree falls
- Mutations
- Plants growth
- movement
- competition
- adding heat
- contamination
- Dehydration

Answer:
Mutations