I believe its the first two options.
Answer:
Common pronouns include I, me, mine, she, he, it, we, and us.
It relates to what kind of document you are going to write. It is very important to know appropriate tone of writing. Documents usually have a formal tone. This tone is used in reports, instructions and other business docs. You can't use slang, bad words etc in formal toned docs. Also your writing should to sound natural so don't make your docs stuffy.
I would go with although both elephants,Asian and African elephants ate different in size ,genetics and habitat
