Answer:
The first one: "Although both are elephants, Asian and African elephants are different in size, genetics, and habitat." is better because the thesis statement is supposed to be an introduction to your essay.
Explanation:
Meaning that it introduces the audience to the different topics that you're going to later bring up in the body paragraphs.
Think of the thesis as the entire purpose of your essay being condensed into one sentence.
Hope this helps you :)
