Hi!
Some of the most common causes of iron deficiency anemia include chronic blood loss (chronic kidney deisease) and loss of iron in the blood.
Scientists use several methods to determine the proximity between species. Two of those methods may be an anatomical comparison, by examining the skeleton structure of two species, and DNA composition comparison, by comparison of genes, or specific parts of the DNA, that allow establishing the relative distance between species.
The right answer is it can be attributed to similarities among organisms in proteins and nucleic acids (especially in their coding regions in their genome).
Genomes consist of coding regions, which correspond to genes, and non-coding regions. The coding part is the one that gives the proteins that are involved in the structure and metabolism of the individuals. if two individuals have a similar protein-giving genome, then they will probably have the same structure and metabolism.