Answer:
Formal
Step-by-step explanation:
This writing sample can best be classified as formal. We can see that the subject matter is a serious one, and one that conveys accurate scientific facts, as opposed to personal, biased or irrelevant information. Moreover, the sentence is written in a way that would appeal to readers with some level of education. Finally, we can see that the language is proper enough that it could appeal to all audiences without any risk of being offensive or overly casual.