Ascientist has analyzed the chemicals that make up a sample of an unknown substance. which chemicals would be the best indicator that the unknown substance is a plant a. fructose and sucrose b. sucrose and oxygen c. nitrogen and phosphorous d. cellulose and starch

D. Cellulose and starch

Cellulose and Starch.

Explanation:

The cellulose is the chemical component that is found only  in the plant cell which proves that the substance is obtained from the plant cell.

The starch is the stored form of glucose which is found in the plant cell. The product of photosynthesis is glucose and it is stored in the plant cell in the form of starch.

So, presence of both of the substances states that it is plant cell.