Question

how does the gaseous exchange takes place at blood level

Answer 1

Gaseous exchange happens by the process of Diffusion. Oxygen and Carbon-di-oxide move between the lungs and the blood due to the difference in concentrations. When the blood surrounding the alveoli has lower concentration in oxygen than the air which has just been inhaled, Oxygen moves to the blood. Similarly when the blood has higher concentration of Carbon-di-oxide than in the alveoli, it moves into the lungs from where it is exhaled. 

Answer 2

Answer:Gas exchange takes place in the millions of alveoli in the lungs and the capillaries that envelop them. As shown below, inhaled oxygen moves from the alveoli to the blood in the capillaries, and carbon dioxide moves from the blood in the capillaries to the air in the alveoli

Explanation: