Humans require transport systems to supply their cells and remove waste products. Gas exchange occurs in the lungs and food molecules are absorbed by the digestive system.
What happens to red blood cells as they pass through the capillaries in the lungs?
Carbon dioxide diffuses from the air in the alveoli into the red blood cells and attaches to their haemoglobin
Oxygen diffuses from the air in the alveoli into the red blood cells and attaches to their haemoglobin
Oxygen is released from the haemoglobin in the red blood cells and diffuses into the air in the alveoli
Which of the following products of digestion are transported in the blood capillaries of the villi?
Amino acids and glucose
Glucose and fatty acids
Fatty acids and amino acids
Which structure in the diagram below transports the products of fat digestion?
In mammals, why must oxygen and nutrients from food be absorbed into the bloodstream for delivery to cells?
Which of the following blood vessels allow the exchange of materials at cellular level?