Number 3
Snnsbsbsbsnnsnsjsnensns didn’t
Simple. Air has mass. And if air has mass it also has weight. You can feel air when the wind blows. Or do an experiment. Weigh an empty container. Then pump it to a vacuum. Weigh it again. The difference is the weight of the air inside.
Enzymes are not used in the reaction so usually the enzyme will sort of reset and be ready to use in another reaction . this is because enzymes are proteins and their shape is what they use in a chemical reaction so when the reaction is done the product is released (the reaction) and the enzyme can relax and go back to its normal shape
I’m not sure but I’m guessing the answer would be the first one !