Answer: Enzymes are organic bio-molecules that catalyze the chemical reactions in biological system. Similar to catalyst, an enzyme accelerates the rate of a chemical reaction and it is neither consumed nor changed in the reaction. Therefore, the enzymes are also called bio-catalysts.
Explanation:
The patellar reflex or knee(j)erk reflex doesn't happen when your leg is straight because the tendon is relaxed. In order for the reflex to be elicited, the tendon must be flexed or stretched.
I think it’s the first one - a , but I could be wrong