At a glance this one's confusing, I agree.
Genetic engineering has made it easier for forensic scientists to differentiate human DNA beyond simple blood sampling. This inevitable led to release of innocent accused prisoners.
Option C is the basic definition of a species. Can you think of some examples of plants or animals that satisfy A, B, or C that are not the same species?
B. Heart, because the heart circulates blood throughout your body.
Answer:
because cells build tissues, tissues build organs, organs build organ system.