Question

energy sources
by jennifer greene
in the past, conventional energy sources such as coal and oil were the main sources of energy. both coal and oil are examples of fossil fuels. fossil fuels form from the remains of organisms buried deep under the earth. with time, the remains compress under extreme heat and pressure. this is a slow process that occurs over millions of years. this means fossil fuels take a very long time to form. moreover, fossil fuels are nonrenewable, which means they are limited in supply, and one day we will run out of them. this has caused scientists and environmentalists to look for renewable energy sources—sources that can keep being replenished.
wind, solar, geothermal, and hydroelectric power are examples of renewable energy sources. giant wind turbines capture wind energy for later use. wind farms containing many of these turbines are popping up all over the world. solar energy—energy from the sun—is harnessed using solar panels, which absorb heat from the sun to generate electricity. geothermal energy refers to energy derived from the heat in the earth. hydroelectric energy is electricity produced from the force of flowing water. often, a river is dammed to create a reservoir to
what is the central idea of the passage?
a. wind and solar are the most important and most effective energy sources.
b. conventional energy sources will run out, and people are finding ways to use different renewable sources of energy.
c. energy sources are divided into conventional and renewable energy sources, and both sources are equally important.
d. coal and oil are the most important and most effective energy sources.

Explanation:

The passage first mentions that conventional energy sources (fossil fuels like coal and oil) are non - renewable and will run out. Then it talks about the search for renewable energy sources (wind, solar, geothermal, hydroelectric). Option B captures this main idea.
Option A only focuses on wind and solar and ignores the context of conventional energy sources running out. Option C says both conventional and renewable are equally important, but the passage emphasizes the need for renewable as conventional will be exhausted. Option D is incorrect as the passage is moving away from coal and oil being the main focus.

Answer:

B. Conventional energy sources will run out, and people are finding ways to use different renewable sources of energy.