Question

which process is responsible for oxygen moving from lungs into blood? a) active transport b) diffusion c) osmosis d) exocytosis

Explanation:

• Option A: Active transport requires energy (ATP) to move substances against a concentration gradient. Oxygen moves from lungs (higher concentration) to blood (lower concentration) down a gradient, so not active transport.
• Option B: Diffusion is the movement of particles from an area of higher concentration to lower concentration. In lungs, oxygen concentration in alveoli is higher than in blood, so oxygen diffuses into blood. This matches.
• Option C: Osmosis is the diffusion of water across a semi - permeable membrane. It does not involve the movement of oxygen, so this is incorrect.
• Option D: Exocytosis is the process by which cells release substances (like hormones, waste) out of the cell. It is not related to oxygen movement from lungs to blood.

Answer:

B) Diffusion