GED Science Test #7 3

Question 1

What process do plants use to convert carbon dioxide and water into glucose using sunlight?

Accepted Answer

Photosynthesis

Answer

Photosynthesis is the process by which plants, algae, and some bacteria use light energy (usually from the sun) to convert carbon dioxide and water into glucose and oxygen.

Question 2

A substance has a pH of 2. How would you classify this substance?

Accepted Answer

Strongly acidic

Answer

The pH scale runs from 0 to 14. A pH of 7 is neutral, values below 7 are acidic, and values above 7 are basic. A pH of 2 indicates a strongly acidic substance.

Question 3

Which layer of the atmosphere contains the ozone layer that protects Earth from ultraviolet radiation?

Accepted Answer

Stratosphere

Answer

The ozone layer is located in the stratosphere, approximately 15–35 km above Earth's surface. It absorbs most of the sun's harmful ultraviolet (UV) radiation, protecting life on Earth.

Question 4

In an experiment, a scientist changes only one variable while keeping all others constant. The variable that is changed is called the:

Accepted Answer

Independent variable

Answer

The independent variable is the one that the scientist deliberately changes or manipulates in an experiment to observe its effect. The dependent variable is what is measured in response to those changes.

Question 5

Which of the following is an example of a physical change rather than a chemical change?

Accepted Answer

Dissolving sugar in water

Answer

Dissolving sugar in water is a physical change because no new substance is created — the sugar molecules remain unchanged and can be recovered by evaporating the water. The other options all involve chemical reactions that create new substances.

GED Practice Test

GED Practice Test

GED Science Test #7 3