<prompt> At the end of 5th week of gestation, how many numbers of somites can be seen?24263844  <response>: The first pair of somites arises in the occipital region of the embryo at approximately the 20th day of development, from here new somites appear in craniocaudal sequence at a rate of approximately three pairs per day until at the end of the fifth week 42 to 44 pairs are present Ref: Grays 39ep-210-220 