Its is already a balanced equation so the option a.1 would fill in for the blank.
Mass does<span> not </span>affect<span> the </span>acceleration<span> due to gravity in any measurable way. The two quantities are independent of one another. Light </span>objects<span> accelerate more slowly than heavy </span>objects<span> only when forces other than gravity are also at work. When this happens, an </span>object<span> may be falling, but it is not in free fall.
Mass does matter when pointed in a downward angle, like if you have a metal toy car racing down a large peice of wood at a downward angle. If you had a plasitic car aong side it to measure which would go faster the metal car will reach the bottom quicker, gravity weighs down things :)</span>
I believe it is DNA: deoxyribonucleic acid
