What is the dominant pigment in muscle tissue when exposed to oxygen?

Myoglobin is the dominant pigment in muscle tissue when exposed to oxygen because it serves as the primary oxygen-binding protein found in muscle cells. Myoglobin's role is crucial in facilitating oxygen transport and storage in muscle tissues, allowing for efficient aerobic metabolism during physical activity. This pigment contains a heme group that can bind to oxygen, sustaining muscular function and endurance during exercise.

While hemoglobin is also related to oxygen transport, it is primarily found in red blood cells rather than muscle tissue. Collagen is a structural protein that provides strength and support to connective tissues and is not involved in oxygen transport. Chlorophyll is the green pigment in plants that plays a role in photosynthesis, which is unrelated to muscle tissue and its function in animals. Hence, myoglobin's specific role and presence in muscle cells make it the correct choice as the dominant pigment under oxygen exposure.