Which can be used between two independent clauses?

What would happend if organ systems failed to work together

What is in his westrose president lincoln central claim in the speech

Which best compares the authors’ purposes in silent spring and “save the redwoods”? both authors want readers to protect human rights. both authors want readers to focus on saving trees. both authors intend to entertain readers with their essays. both authors intend to convince readers of their viewpoint.