Question

which colour of blood does octopus have and Why?​

Answer 1

Octopuses have blue blood. To survive in the deep ocean, octopuses evolved a copper rather than iron-based blood called hemocyanin, which turns its blood blue

Answer 2

The colour of blood of octopus is blue. It is due to the presence of haemocyanin , which is responsible for keeping the species alive even at extreme temperatures.

Haemocyanin are metalloprotein contain copper atoms which are reversily bonded to two oxygen atoms.