Which molecule allows a blade of grass to stand up straight?

The correct answer is polysaccharide.

Explanation:

The molecule, which permits a blade of grass to stand upright is known as the polysaccharide mainly the cellulose.  Cellulose is an essential polysaccharide and is the mostly found organic compound on the planet Earth. It is utilized in plants for structural activities. It is the prime constituent of the walls of the cells. It is the component that helps the stem of the plants to get strong and helps them to stand in an upright manner.

answer; i believe the correct answer is ( proteins );