Question

which greenhouse gas is most responsible for global warming?
oxygen
carbon dioxide
nitrogen
hydrogen
which of the following is a renewable energy source that helps reduce climate change?
natural gas
coal.
solar power.
nuclear energy
which of these organelles are found only in plant cells?
cell membrane
mitochondria
chloroplast
vesicle

Explanation:

• For the first question: Carbon dioxide is a major greenhouse gas contributing to global warming. Oxygen, nitrogen, and hydrogen are not significant greenhouse gases in this context.
• For the second question: Solar power is a renewable energy source. Natural gas and coal are fossil fuels (non - renewable), and nuclear energy has issues like radioactive waste and is not as widely considered a clean - cut renewable in the same sense as solar in terms of climate change reduction (though it is low - carbon).
• For the third question: Chloroplasts are unique to plant cells as they are involved in photosynthesis. Cell membranes, mitochondria, and vesicles are found in both plant and animal cells (with some differences in vesicle types and functions but they are not exclusive to plant cells).

Answer:

• First question: carbon dioxide
• Second question: solar power
• Third question: chloroplast