GED Science Test #4 2 — Questions and Answers
Question 1: Which organelle is responsible for producing energy (ATP) in a cell?
- Mitochondria (Correct answer)
- Ribosome
- Nucleus
- Vacuole
Correct answer: Mitochondria
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:
- Phototropism (Correct answer)
- Photosynthesis
- Photoperiodism
- Phototaxis
Correct answer: Phototropism
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:
- Convection currents in the mantle (Correct answer)
- The gravitational pull of the Moon
- Solar radiation heating Earth's surface
- Volcanic eruptions at the surface
Correct answer: Convection currents in the mantle
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?
- Independent variable (Correct answer)
- Dependent variable
- Control variable
- Confounding variable
Correct answer: Independent variable
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?
- Physical change (Correct answer)
- Chemical change
- Nuclear change
- Biological change
Correct answer: Physical change
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.
Question 6: Which of the following best describes natural selection?
- Organisms with traits better suited to their environment survive and reproduce more (Correct answer)
- Organisms consciously develop traits they need over their lifetime
- All organisms in a species evolve at the same rate
- Mutations always improve an organism's chances of survival
Correct answer: Organisms with traits better suited to their environment survive and reproduce more
Natural selection, proposed by Darwin, states that individuals with advantageous traits are more likely to survive and pass those traits to offspring. Over generations, these traits become more common in the population.
GED Science Test #4 2
Which organelle is responsible for producing energy (ATP) in a cell?