Question

which gases contribute to the greenhouse effect?
○ nitrogen and helium
○ carbon dioxide and methane
○ carbon dioxide and helium
○ nitrogen and methane

Explanation:

To determine which gases contribute to the greenhouse effect, we analyze each option:

• Nitrogen ($N_2$) and helium ($He$) are not greenhouse gases. Nitrogen makes up most of the atmosphere but doesn't trap heat, and helium is inert and doesn't contribute to the greenhouse effect. So the first and third options are incorrect.
• Carbon dioxide ($CO_2$) and methane ($CH_4$) are well - known greenhouse gases. Carbon dioxide is released from burning fossil fuels, deforestation, etc., and methane is released from sources like livestock, landfills, and natural gas production. Both trap heat in the atmosphere.
• Nitrogen is not a greenhouse gas, so the fourth option (nitrogen and methane) is incorrect.

Answer:

B. carbon dioxide and methane