The solution: Enzyme X works best and increases the rate of reaction at an acidic pH (less than 7) of about two2️⃣ ! Enzyme Y is very very very very very very very very very very very very very very very very very efficient @ slightly acidic pH i.e., slightly less than seven!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!! Enzyme Z is most efficient at an alkaline pH (more than 7!!!). And alkali means a base which is soluble in water. In humans, gastric juice of stomach (a J-shaped bag with thick inner walls. Meh.) has pH in the range of 1.5-2.5, where enzymes such as pepsin, rennin etc. carry out the digestion of food. Thus, enzyme X can be found in stomach. Similarly, the saliva in the mouth of humans has sliiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiightly acidic pH of 6.8, where salivary amylase enzyme is moooooooooooooooooooooooooooooooooooooooost effective! Thus, enzyme Y can be found in the buccal cavity. Small intestine has slightly alkaline pH of 7.8, where enzymes such as trypsin help in digestion of food. So, enzyme Z can be found in duodenum. Morus Alba is the scientific name of mulberry.