3

Motion

4

Niagara Falls

4

Hoover Dam

2

Who Works Here?

3

Neil Armstrong

4

How they Work? Trains

4

Felix's Independence Day

3

Astronauts

4

Mount Fuji, Japan

3

Space Exploration

3

Pollution

3

Bus Driver

4

Gorillas and Other Primates

4

Maddy's New Hampshire Diary

4

Okavango Delta, Botswana

3

Meteorites, Meteoroids, and Meteors

3

Firefighter

2

Lake Day

3

Comets

3

Police Officer

4

Victoria Falls, Zimbabwe/Zambia