While testing for biological macromolecules in an unknown, you find that it reacts strongly with iodine and the solution immediately turns a very dark black. The macromolecule at hand must be:.

The macromolecule must be starch.

Explanation:

Starch is a polymer of Glucose joined by glycosydic bond.

Starch is the main energy storage substance in green plants.

Starches react with iodine and give a bluish black or black color and thus iodine test is considered as a confirmatory test for starches.

In this experiment ,the solution turns very dark black on addition of iodine so we can be sure that the solution contained starch.

d

explanation:

the higher the instrument the better