Which two body systems are directly involved in movement? OPTIONS:
- muscular and skeletal
- digestive and muscular
- skeletal and respiratory
- respiratory and digestive
A: muscular and skeletal

Which human activity has most negatively affected air quality? OPTIONS:
- burning coal
- growing crops
- using solar energy cells
- constructing nuclear power plants
A: burning coal

What tool is used to determine the mass of an object? OPTIONS:
- Balance
- Meter stick
- Thermometer
- Graduated cylinder
A: Balance

In order to survive, all organisms must have OPTIONS:
- chlorophyll
- carbon dioxide
- energy
- blood
A:
energy