What is popcorn made up of a: corn b: small acorns c: big acorns d: or none of the above

Of the pollutants that form acids in the atmosphere, which is easiest to reduce? a. sulfur dioxide b. nitrogen dioxide c. ozone d. carbon monoxide

Factors that can increase mutation rates a. high temps b. low temps c. food additives d. uv rays

How does the nervous system affect the excretory system?