What mutation would cause a protein to be shorter then normal?

Look at the following answer choices and determine which belongs in the both category. testable, can be disproven explains natural phenomena, has evidence to support it prediction, tentative, one or more scientists working together well established, many different scientists working independently, highly reliable

Acceleration is a direct result of a.) balanced forces b.) unbalanced forces c.) gravity d.) velocity

The third stage of cellular respiration is (2 points)