Question: Choose your answer.

Scientists estimate that Maryland contains more than 850 million tons of coal. Coal is most commonly used to produce ___.

OPTIONS:
- electricity
- medicine
- metals
- water
My Answer: electricity

Question: Choose your answer.

In order for a glider to fly, its weight must be opposed by

OPTIONS:
- lift.
- drag.
- gravity.
- friction.
My Answer: lift.

Question: Choose your answer.

Signs in many stores and restaurants warn that microwaves are in use. What is the main reason for this warning?

OPTIONS:
- Some people do not like food cooked in microwave ovens.
- Microwaves sometimes affect people's sense of sight.
- Microwaves sometimes cause hair or teeth to fall out.
- Some people have pacemakers that may be affected by microwaves.
My Answer: Some people have pacemakers that may be affected by microwaves.

Question: Choose your answer.

Light rays are focused by the lens of a camera through the process of

OPTIONS:
- reflection.
- refraction.
- dispersion.
- diffraction.
My Answer:
refraction.