Random question?

Which event would most likely occur if the number of nitrogen fixing bacteria were reduced within an ecosystem?

Random question?

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?

Random question?

When oxygen combines with hydrogen, which substance is formed?

Random question?
Which object is nonliving?