The relationship between cell phone use and the incidence of brain tumors is still unclear, this is because some studies show a causal relationship while others do not. is still unclear, this is because some studies show is still unclear; some studies show are still unclear because some studies show...

Wind resistance created by opening windows while driving results in a fuel penalty as great or greater than is incurred by using air conditioning. (A) as great or greater than is incurred by using air conditioning (B) that is as great or greater than is incurred using air conditioning (C) as great a...