Which groups primarily use hemocyanin as their respiratory pigment?

Which groups primarily use hemocyanin as their respiratory pigment?

• A. Mollusks and annelids.
• B. Crustaceans and arachnids.
• C. Mammals.
• D. Insects.

Answer: (B)

Hemocyanin is a copper-containing pigment that carries oxygen in the blood of many mollusks and arthropods, giving their blood a blue color when oxygenated. Among the options, crustaceans and arachnids are arthropods that commonly rely on hemocyanin to transport oxygen in their hemolymph. In contrast, mammals use hemoglobin, insects primarily rely on a tracheal system for gas exchange with little circulating pigment, and many annelids use hemoglobin or other pigments rather than hemocyanin. So, crustaceans and arachnids best fit as the groups primarily using hemocyanin.

Hemocyanin is a copper-containing pigment that carries oxygen in the blood of many mollusks and arthropods, giving their blood a blue color when oxygenated. Among the options, crustaceans and arachnids are arthropods that commonly rely on hemocyanin to transport oxygen in their hemolymph. In contrast, mammals use hemoglobin, insects primarily rely on a tracheal system for gas exchange with little circulating pigment, and many annelids use hemoglobin or other pigments rather than hemocyanin. So, crustaceans and arachnids best fit as the groups primarily using hemocyanin.