Here's why:
* Evolutionary Relatedness: Cytochrome c is a protein involved in cellular respiration, a fundamental process for all living organisms. The amino acid sequence of cytochrome c is highly conserved across species, meaning it has changed very little over evolutionary time. This conservation suggests its critical role in life.
* Phylogenetic Tree: Animals that are more closely related on the evolutionary tree will share more similar genetic material, including their cytochrome c sequences. Mammals are a group within the vertebrate lineage, and dogs belong to the order Carnivora.
* Other Mammals: Other mammals, such as cats, horses, cows, or even humans, would likely have cytochrome c sequences more similar to that of a dog than animals from different classes, like reptiles, amphibians, birds, or fish.
Important Note: While mammals are expected to have the most similar cytochrome c, the actual degree of similarity can vary depending on the specific mammal species.