1. What force, created when two surfaces rub together,
makes it difficult to drag a large object across the
ground?
A gravity
B friction
C lift
D drag
2. Which of the following do many scientists think
caused the extinction of the dinosaurs?
A an asteroid
B freezing temperatures
C wildfires
D all of the above
3. All lobster shells contain __________, compounds that
give lobsters their color.
A melanin
B DNA
C pigments
D dye
4. Nitrogen dioxide, a major air pollutant, is a gas
produced mainly by __________.
A cars
B cow farts
C factories
D wildfire smoke
5. The most common cause of concussions among high
school football players is __________.
A contact with another player
B hitting the ground
C crashing into equipment
D practicing too hard
6. __________ of the elements on the periodic table are
found in nature.
A 100%
B Around 75%
C About 50%
D Less than 50%
7. Emeralds form when elements in __________ are
heated and pressed together.
A rocks
B Earth’s crust
C Earth’s core
D lava
8. Lobsters usually have brown shells, but some can be
different colors due to __________.
A an adaptation
B a mutation
C an environmental factor
D a change in pH
9. During which time of year is air pollution the highest
in London?
A Summer
B Spring
C Winter
D Fall
10. Dinosaurs became extinct about __________ years
ago.
A 65 million
B 6.5 billion
C 65,000
D 6,500
