Question

which author is the best source for a project on renewable energy that focuses specifically on geothermal energy?
an engineer who works on the federal governments renewable energy research programs
an inventor of a new geothermal system who is looking for financial backers
a popular science writer who writes features for general interest magazines
an engineer who works for a company that produces and installs geothermal systems

Explanation:

An engineer working on the federal government's renewable energy research programs is likely to have comprehensive, objective, and up - to - date knowledge about geothermal energy as part of the broader renewable energy context. The inventor looking for financial backers may have a biased view (to promote their system). The popular science writer may not have in - depth technical knowledge. The engineer from a company producing and installing geothermal systems may have knowledge limited to their company's products rather than a broad view of geothermal energy.

Answer:

an engineer who works on the federal government's renewable energy research programs