Concept:Vegetables supply essential nutrients needed by the body for growth and maintenance.
Explanation:Vegetables are rich in mineral salts such as magnesium, iron, and calcium.
These mineral salts are essential for body growth and various metabolic functions.
Chlorophyll and glucose are produced by plants, but they are not the main essential substance obtained from eating vegetables.
Carbon dioxide is a gas used by plants, not a nutrient stored in vegetables for humans.
Therefore, the required essential substance in vegetables is mineral salts.
Answer:C. Mineral Salts