Q: Fact 1: Antigens are molecules that the immune system recognizes as foreign to the body. Fact 2: Antigens are proteins foreign to the body. Given the two facts above, what are antigens?

OPTIONS:
- animals
- negative
- positive
- complex
- proteins
- PDAs
- humans
- parasites

A: proteins

Q: Fact 1: Population size influences the chances of a species surviving. Fact 2: Each species lasts for a time, sometimes surviving to the present and sometimes going extinct. Given the two facts above, what influences the chances of going extinct?

OPTIONS:
- cloud cover
- Population size
- Pollution
- Pesticides
- rainfall
- risky population
- Climate change
- the environment

A: Population size

Q: Fact 1: Vein deposits of gold and silver are formed by igneous intrusion. Fact 2: Intrusive igneous rocks form underground. Given the two facts above, where are gold and silver formed naturally?

OPTIONS:
- inactive
- Near platinum alloys
- electrically
- aqueous solution
- eukyarotes
- In a royal palace
- Above ground
- Underground

A: Underground

Q: Fact 1: Most salamanders use their sense of smell to find a mate. Fact 2: Salamanders are a type of amphibian. Given the two facts above, what uses their sense of smell to find a mate?

OPTIONS:
- eyes
- members of their own species
- passenger pigeons
- Something that is self-aware
- a type of amphibian
- plants
- eat plants or other animal
- h2o

A:
a type of amphibian