What is the primary difference between a circular pathway and a linear pathway?

circular pathways are able to accommodate multiple entry and exit points, in a linear pathway, one trip through the pathway completes the pathway

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.