Nutrient Delivery to Active Muscle Tissue

Steps:

• Muscle cells require glucose and oxygen for aerobic respiration to produce ATP.
• Blood plasma carries higher concentrations of glucose and oxygen than tissue fluid during activity.
• These substances diffuse net from plasma into tissue fluid down concentration gradients.
• Waste products like CO2 and lactic acid, produced by muscles, diffuse in the opposite direction.

Why C is correct:

• Glucose and oxygen move from plasma to tissue fluid via simple diffusion, driven by Fick's law of diffusion (rate proportional to concentration gradient).

Why the others are wrong:

• A: CO2 and lactic acid are metabolic wastes diffusing from tissue fluid to plasma.
• B: CO2 diffuses out of tissue fluid; only glucose moves in.
• D: Lactic acid diffuses out of tissue fluid; only oxygen moves in.

Final answer: C