Forensic anthropologists are trying to determine the age of a male skeleton that has been uncovered. They conclude that he must have been between 16 and 19 judging by the measurement of his ribs
clavicle
pelvic bone
tibia

the correct answer is: b. pantala flavescens, because these organisms would have a high level of genetic variation due to sexual reproduction.  

because involves two organisms (parents) whose genetic material combines, sexual reproduction leads to genetic variation in new generations of offspring. the offspring is an unique organism, with new genome, more protected with the higher ability to adapted. this process is fundamental to evolution.