GED Science Test #4 2

Question 1

Which organelle is responsible for producing energy (ATP) in a cell?

Accepted Answer

Mitochondria

Answer

Mitochondria are the "powerhouses of the cell," producing ATP through cellular respiration. They have a double membrane structure that allows them to generate energy efficiently.

Question 2

A scientist observes that plants placed near a window grow toward the light. This response is called:

Accepted Answer

Phototropism

Answer

Phototropism is the growth response of a plant toward (or away from) light. It is caused by the unequal distribution of auxin, a hormone that stimulates cell elongation.

Question 3

The tectonic plates of Earth are constantly moving. This movement is driven primarily by:

Accepted Answer

Convection currents in the mantle

Answer

Convection currents in the semi-liquid mantle transfer heat from Earth's interior, driving the movement of tectonic plates. Hot material rises, spreads, cools, and sinks in a cycle.

Question 4

In an experiment, which variable does the scientist deliberately change?

Accepted Answer

Independent variable

Answer

The independent variable is the one the researcher manipulates. The dependent variable is what is measured in response. Control variables are kept constant to ensure a fair test.

Question 5

Water (H₂O) changes from liquid to gas during evaporation. What type of change is this?

Accepted Answer

Physical change

Answer

Evaporation is a physical change because the water molecules do not change — only the state (phase) changes. No new substance is formed; the chemical formula remains H₂O.

GED Practice Test

GED Practice Test

GED Science Test #4 2