Question

Which thing is green in morning,black in noon,blue in evening,white at night?

Answer 1

Hi friend,
I think the answer shall be The colour of algae.
I heard it somewhere that the algae looks green in morning, black in noon, blue in evening and white at night.

Answer 2

The right answer is Blue-green Algae.

Blue-green algae seems green in morning, black in noon, blue in evening and white in night.

that's why it is called blue-green algae.