Google - Respiratory pigments in animals a. are needed because the concentration of oxygen is?

... low in physiological fluidb. are always packaged into erythrocytesc. bind irreversibly with oxygend. work independently of the partial pressure o

... low in physiological fluid
b. are always packaged into erythrocytes
c. bind irreversibly with oxygen
d. work independently of the partial pressure of oxygen
e. are only found in vertebrates

or:... low in physiological fluidb. are always packaged into erythrocytesc. bind irreversibly with oxygend. work independently of the partial pressure of oxygene. are only found in vertebrates

Tags:work,animal,concentration,partial,always,