Question

which animal has blue blood

Answer 1

Octopus has blue blood because it contains protein called harmocyanin.

Answer 2

Answer: Octopus as blue blood because:

The ability is literally in their blood. The same pigment that gives the octopus blood its blue color, hemocyanin, is responsible for keeping the species alive at extreme temperatures. Hemocyanin is a blood-borne protein containing copper atoms that bind to an equal number of oxygen atoms.