Concept:Some animals transport oxygen using hemoglobin that is not contained inside red blood cells.
Explanation:Earthworms have red blood because their blood contains hemoglobin.
However, this hemoglobin is dissolved directly in the blood plasma.
Earthworms do not have red blood cells at all.
They exchange gases through their moist skin instead of using blood cells for oxygen transport.
Frogs, snakes, and peacocks all possess red blood cells containing hemoglobin.
Therefore, the animal without red blood cells is the earthworm.
Answer:Earthworm