A) A coal burning generator
B) A wood burning stove
C) An automobile that operates on fuel cells
D) A gasoline burning automobile

A) Heat from within the Earth's crust
B) The sun
C) The moon
D) Running water

A) The number of clouds in the sky
B) The amount of moisture in the air
C) The state of the atmosphere at any particular time
D) The speed of the wind

A) Rotation
B) Atmosphere
C) Magnetic Field
D) Temperature

A) The sun protects life on Earth
B) The sun damages life on Earth
C) The sun powers life on Earth
D) The sun causes plants to wither and die

A) The Earth's rotation
B) The Earth's changing distance from the sun
C) The tilt of the Earth on it's axis
D) Changes in the sun's intensity

A) It reflects light from Earth
B) It makes it's own light
C) Because it reflects sunlight
D) It reflects light from stars

A) Sunken plains, or seas
B) High plateaus
C) Deep craters
D) Mountains

A) Motion
B) Light
C) Heat
D) Electricity

A) Motion and time
B) Lift and thrust
C) Wind and rain
D) Temperature and pressure