ICAS Science 4

Question 1

Which of the following best describes a food web?

Accepted Answer

A network of interconnected food chains in an ecosystem

Answer

A food web shows the complex feeding relationships among multiple organisms in an ecosystem, with many overlapping food chains.

Question 2

Water changes from a liquid to a solid when it is cooled to 0°C (32°F). This process is called:

Accepted Answer

Freezing

Answer

Freezing is the phase change from liquid to solid that occurs when water loses enough thermal energy at 0°C.

Question 3

A student sets up an experiment with two identical plants. One receives water daily, the other does not. What is the independent variable?

Accepted Answer

Whether or not the plant receives water

Answer

The independent variable is the factor deliberately changed by the experimenter — in this case, whether the plant receives water.

Question 4

Which of the following is a renewable source of energy?

Accepted Answer

Solar power

Answer

Solar power is renewable because sunlight is continuously available and cannot be depleted, unlike fossil fuels.

Question 5

A ball is rolled along a smooth floor and eventually stops. The force that caused it to stop is:

Accepted Answer

Friction

Answer

Friction between the ball and the floor surface converts kinetic energy into heat, gradually slowing and stopping the ball.

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