Final answer:
The reddish brown color of skeletal muscle is due to the presence of myoglobin, a protein that binds oxygen and aids in aerobic respiration.
Step-by-step explanation:
The characteristic reddish brown color of skeletal muscle comes from the substance called myoglobin. Myoglobin is a protein that binds oxygen in muscle cells, similar to hemoglobin in the blood. It provides the muscle tissue with the oxygen needed during periods of activity.
The presence of myoglobin allows muscles to maintain aerobic respiration and is responsible for the distinct color of skeletal muscles.