Actually its an adjective
Answer:
The most straightforward theory for Western Rome's collapse pins the fall on a string of military losses sustained against outside forces.The Roman Empire was very successful, but perhaps its failings started right at the beginning
Explanation:
The answer is 2.
Enzymes work to speed up chemical reactions by changing what goes into the reactions (substrates) into different molecules. To do so, these enzymes bind with the substrates, making the physical form very important. The lock and key method explains that enzymes and their corresponding substrates are shaped very specifically to be able to fit into one another to undergo this change.
The team stretched their legs, practiced their drills and rehearsed their set plays.