QUESTION: 25

Earth's atmosphere contains naturally-occurring ozone. Ozone, which contains three oxygen atoms joined together (O3), forms a layer miles above Earth's surface. The layer serves as a shield from the harmful ultraviolet rays of the Sun.
A group of chemicals called CFCs (chlorofluorocarbons) are used as refrigerants, propellants, and cleaning solvents. At Earth's surface CFCs are chemically stable. However, CFC molecules can be broken apart high in the atmosphere and they can destroy the protective ozone layer.
Based on the information, which action would reduce the destruction of the ozone layer?

Limit the production and use of CFCs.
Use ultraviolet sunscreen more frequently.
Plant more oxygen-producing trees.
Build many ozone-producing plants.
Research ways to convert more ozone into oxygen.

Answer(s): A

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QUESTION: 26

There are usually thirty-two teeth in the mouth of an adult human. They are divided into four groups: incisors, canines, premolars, and molars. The diagram below shows the arrangement of these teeth in the mouth.

Which statement best explains why your teeth have so many shapes?

The different shapes allow all of the teeth to fit in your mouth.
All the teeth in your mouth are used for the same purpose.
The different shapes had a purpose in prehistoric man but not in the modern man.
Teeth allow you to swallow more effectively.
Each tooth has a specialized biting or chewing function.

Answer(s): E

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QUESTION: 27

The nightshade family of plants includes more than 2000 species of herbs, shrubs, and small trees. Plants with edible parts include the potato, tomato, eggplant, and red pepper. Some nightshade members such as jimsonweed and belladonna contain poisonous substances. Tobacco and petunias are also in the nightshade family.
Which of the following most accurately describes the entire group of plants in the nightshade family?

poisonous plants
edible plants
no economically important species
no agriculturally important plants
a large variety of species

Answer(s): E

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QUESTION: 28

Burning paper requires the chemical combination of oxygen in the air with the material composing the paper. Which would cause the paper to burn faster?

wetting the paper before burning
using a thicker piece of paper
using only pastel shades of paper
putting the burning paper in a closed container
increasing the oxygen around the paper

Answer(s): E

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QUESTION: 28