For the following questions answer them individually
Out of 'X' pairs of ribs in humans only 'Y' pairs are true ribs. Select the option that correctly represents values of X and Y and provides their explanation :
Adult human RBCs are enucleate. Which of the following statement(s) is/are most appropriate explanation for this feature?
(a) They do not need to reproduce
(b) They are somatic cells
(c) They do not metabolize
(d) All their internal space is available for oxygen transport