The right answer is D. renal regulation.
Among the many factors that modulate tension (vessels, heart strength, blood volume ...), the kidney plays a vital role because it makes an enzyme called renin that helps increase blood pressure and it regulates the outflow of sodium and water, which contribute to the elevation or diminution of blood pressure in the arteries.
The lack of iron makes them crave ice.
MRNA is a short lived form of genetic information that is used in transcribing the genetic information, hence it is not very useful for analysis since it is fragile and wrong transcriptions happen quite often. SNPs (Single Nucleotide Polymorphisms) are a form of genetic mutation; they are more frequent than most other mutations since a single transription error may lead to this. While SNPs are important in genetic analysis and getting information about causes of disease, they are not very helpful in determining your maternal lineage. Similarly, while nuclear DNA contains a large portion of our genetic information, half of it is from our fathers and half from our mothers, so the analysis becomes hazy very soon. Mitochondrial DNA instead is directly passed down from mother to her offspring since the embryo contains only the mitochondria of the ovary. Thus, studying differences between mitochondrial DNA, one can gain information about his maternal lineage and go back to Mitochondrial Eve, the person from which all living persons have gotten their mitochondria from. Thus, the correct answer is c.
