Carbon Cycle and Greenhouse Effects

Which gas was mostly absent from Earth's early atmosphere?

• Ammonia

• Methane

• Nitrogen

• Free Oxygen

What is the main effect of greenhouse gases like carbon dioxide on Earth?

• They make the atmosphere thinner.

• They absorb heat, making the Earth warmer.

• They create more clouds.

• They help plants grow faster.

How do plants use carbon from the atmosphere?

• They release it back into space.

• They use it to make food and oxygen.

• They store it as water.

• They turn it into light energy.

What does "carbon fixation" mean in the context of plants?

• Plants release carbon into the air.

• Plants change carbon gas into solid compounds.

• Plants burn carbon for energy.

• Plants remove carbon from the soil.

What are the main products created during cellular respiration?

• Carbohydrates and oxygen

• Carbon dioxide, water, and energy

• Light energy and water

• Glucose and carbon dioxide

How do humans release carbon dioxide back into the atmosphere?

• By eating carbohydrates

• By breathing out

• By drinking water

• By growing plants

What do marine animals use carbonate ions for?

• To help them breathe underwater

• To build their shells and skeletons

• To make their food

• To break down rocks

What happens when too much carbon dioxide is released into the atmosphere from burning fossil fuels?

• The air becomes cleaner.

• The Earth's temperature goes down.

• The Earth's temperature goes up.

• More oxygen is produced.