The silurian period occurred                a.  during the hadean eon.      b.  before the neogene period.      c.  during the mesozoic era.      d.  after the permian era.

For a comparative or experimental investigation, scientists often make a testable about a scientific question, and then they test it in the investigation. a.control b.hypothesis c.procedure d.system

Individuals do not compete directly for resources, but are prey for the same predator

This part insulates the reaction chamber from the transfer of heat to or from the surrounding environment