Correct Answer:
B. 1 mm/sec
The approximate blood circulation rate in human capillaries is around 1 mm/sec. This slow velocity is crucial for efficient exchange.
- Blood flow significantly slows down in the capillaries to allow sufficient time for the diffusion of oxygen, nutrients, and waste products between the blood and surrounding tissues.
- If the rate were much faster (e.g., 10 mm/sec or 100 mm/sec), there wouldn't be enough time for adequate exchange, compromising cellular function.
- A rate of 0.1 mm/sec would be excessively slow, potentially leading to insufficient delivery of vital substances and accumulation of waste.
The optimal speed ensures vital physiological exchange.