ICAS Science 4 — Questions and Answers
Question 1: Which of the following best describes a food web?
- A single chain showing what one animal eats
- A network of interconnected food chains in an ecosystem (Correct answer)
- A diagram of how energy is lost as heat
- A list of all producers in a habitat
Correct answer: A network of interconnected food chains in an ecosystem
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:
- Melting
- Condensation
- Freezing (Correct answer)
- Evaporation
Correct answer: Freezing
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?
- The growth of the plants
- Whether or not the plant receives water (Correct answer)
- The type of soil used
- The amount of sunlight each plant receives
Correct answer: Whether or not the plant receives water
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?
- Coal
- Natural gas
- Petroleum
- Solar power (Correct answer)
Correct answer: Solar power
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:
- Gravity
- Magnetism
- Friction (Correct answer)
- Air pressure
Correct answer: Friction
Friction between the ball and the floor surface converts kinetic energy into heat, gradually slowing and stopping the ball.
Question 6: Which organelle is known as the 'powerhouse of the cell' because it produces energy?
- Nucleus
- Ribosome
- Mitochondria (Correct answer)
- Vacuole
Correct answer: Mitochondria
Mitochondria produce ATP (adenosine triphosphate), the main energy currency of the cell, through cellular respiration.
Question 7: Which of the following best describes a hypothesis?
- A proven fact based on many experiments
- A testable prediction about the outcome of an experiment (Correct answer)
- A summary of data collected during a study
- A conclusion drawn after analyzing results
Correct answer: A testable prediction about the outcome of an experiment
A hypothesis is a testable, educated prediction made before conducting an experiment, based on prior observations.
ICAS Science 4
Which of the following best describes a food web?