Answer: Because of mutations, evolution, where we live, who we were descended from, etc.
Hope this helps! :)
Explanation:
This type of mutation is beneficial mutation
Mutations are permanent transmissible changes that occur in an individual’s genetic code. Some of these changes can cause destructive conditions such as sickle cell disease or Down syndrome, while many may not be harmful, and even irrelevant. Sometimes, a mutation that will provide an individual with a benefit may take place. This type of mutation is said to be beneficial. An example is the trichomatic vision of humans which gives humans the ability to perceive, and distinguish between red, green, and blue colors.
The kind of compound that increases the hydrogen ion concentration in a solution is acid.
Im not 100% sure but probably fossils and different types of rocks.