The body of an organism has evolved with different systems and organ systems to perform significant functions during metabolism and survival. This evolvement has occurred gradually.
The development of arterial system and heart is essential to supply oxygen to all organs in the body and to eliminate waste out of body.
Thus, the options (d), (c) and (a) are incorrect.
The body of an organism has evolved with different systems and organ systems to perform significant functions during metabolism and survival. This evolvement has occurred gradually.
Therefore, the correct option is – b. To gradually develop.