In order to have the right balance of calcium and magnesium in your bloodstream, we need a functional gland.

In order to have the right balance of calcium and magnesium in your bloodstream, we need a functional parathyroid gland. These glands control the level of calcium in the blood, bones and body by producing parathyroid hormones. Calcium is one of the most important elements in the body because it is used to control many systems, and magnesium is needed for calcium absorption.

whats the answer to your question?

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.