Based on the evidence available at the time, early models of the solar system stated that all objects in space orbited Earth. In the 16th century, an astronomer reevaluated the evidence and proposed a model of the solar system that is still in use. What part of this model corrected the mistake in previous solar system models?
A: The Sun is at the center of this model.

According to the Big Bang Theory, which element most likely formed first?
A: hydrogen

A scientist plans to investigate the nervous system of sea slugs. What should the scientist do first?
A: Review the research other scientists have done on sea slugs.

Lori owns a house next to the lake. She uses lots of fertilizer to keep her lawn green. Which impact could fertilizing her lawn have on the lake?
A:
an increase in the algae population