Specialized neurons in the brain respond to changes in blood osmolarity (solute concentration). When blood osmolarity strays outside the homeostatic range, these neurons release a neurotransmitter that stimulates neurons of the posterior pituitary, which respond by releasing a different chemical into the blood that will travel via the circulatory system to the kidneys. How would you classify this type of simple reflex.

the answer is :

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.