Question

Read the introduction and first paragraph of an essay about energy sources.

Answer 1

Answer:

9

Explanation:

This sentence mentions the main limitation to creating an energy grid that relies completely on solar power. It is the only sentence that questions the viability of the solar power transformation since the equipment is costly.

Sentence 3 reaffirms the need to stop using energy sources that contaminate. Sentence 7 quotes the current market share of solar energy in the United States, and sentence 8 names two advantages of solar power.