A rancher specializing in racehorses has many buyers for her famous horses. She breeds two of her horses together over several years and, after two successful breedings, unexpectedly produced a dwarf pony. How did this happen?

chemical weathering

explanation:

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.

answer; (a) medicalized;