(i) Why is respiratory pigment needed in multicellular organisms with large body size ? (ii) Give reasons…
(i) Why is respiratory pigment needed in multicellular organisms with large body size ?
(ii) Give reasons for the following :
(a) Rings of cartilage are present in the throat.
(b) Lungs always contain a residual volume of air.
(c) The diaphragm flattens and ribs are lifted up when we breathe in.
(d) Walls of alveoli contain an extensive network of blood vessels.
Solution
(i) Diffusion /Diffusion pressure alone cannot take care of oxygen delivery to all parts of the body.
(ii) Reasons:
(a) To ensure that the air-passage does not collapse.
(b) There is sufficient time for oxygen to be absorbed and for the carbon dioxide to be released.
(c) Chest cavity becomes larger.
(d) Because exchange of gases takes place in the alveoli.