SAVE MY EXAM 2.3 - CHOOSE

What is the primary component of the Earth's atmosphere?

• Oxygen

• Carbon dioxide

• Nitrogen

• Argon

How do nitrogen-fixing bacteria benefit plants?

• They convert ammonia into nitrites

• They transform N₂ gas into usable forms

• They release oxygen for photosynthesis

• They decompose organic material

What is a significant source of methane emissions?

• Photosynthesis in plants

• Respiration in animals

• Wetlands under anaerobic conditions

• Combustion of fossil fuels

Why is eutrophication harmful to aquatic ecosystems?

• It increases dissolved oxygen

• It causes excessive nutrient depletion

• It creates oxygen-depleted dead zones

• It improves biodiversity

Which process removes carbon dioxide from the atmosphere?

• Respiration

• Combustion

• Photosynthesis

• Denitrification

What is the primary human contribution to the nitrogen cycle?

• Fossil fuel combustion

• Use of synthetic fertilizers

• Deforestation

• Overfishing

Which element is most associated with ocean acidification?

• Oxygen

• Carbon dioxide

• Nitrogen

• Methane

What is a key characteristic of a carbon sink?

• It releases more carbon than it stores

• It stores carbon for long periods

• It forms in oxygen-rich conditions

• It is entirely man-made

Which process converts nitrates back to atmospheric nitrogen?

• Nitrogen fixation

• Denitrification

• Ammonification

• Nitrification

Why are coral reefs sensitive to ocean acidification?

• Increased salinity affects their growth

• Acidic water weakens calcium carbonate structures

• They absorb atmospheric nitrogen

• They rely solely on surface nutrients