Answer:
To complete the table, you need to identify the acid present in each substance. Here's the information you're looking for:
Acid Present Substance
Lemon Juice Citric Acid
Vinegar Acetic Acid
Gastric Juice Hydrochloric Acid
Citric acid is present in lemon juice, acetic acid is present in vinegar, and hydrochloric acid is present in gastric juice.
Please note that gastric juice also contains other acids such as pepsin and gastric lipase, but the main acid responsible for the low pH of gastric juice is hydrochloric acid.
Step-by-step explanation: