If only one species is considered the 'fittest', why do we still have so many variation among species?

this is a good question! i'll do some research and come back when i have the answer!

answer; the tunica intima also called tunica interna, consists of elastic fibers,connective tissue and smooth muscle cells;

hello

answer: collecting information/data

reason: the student is going around and asking people questions to collect data

i hope this