Scientifically and religiously speaking, Allah expanded the Earth over time. Dah'aha (دحاها) means expanded, made spherical, balanced, and caused to move. If you ask any scientist, they will tell you that the smaller the planet, the less the gravity, meaning that all creatures can grow bigger and taller. In Adams time (pbuh) the earth was much smaller than it is now and therefore being 90 feet tall is scientifically possible, no matter how much it does not fit our mind in this generation. That is why there used to be gigantic dinosaurs! Think of it, life on earth began 3.8 billion years ago, the earth changes greatly over such a time.
"Its night doth He endow with darkness, and its splendour doth He bring out (with light). And the earth, moreover, hath He extended (to a wide expanse)." [Quran 79:30]
But Christianity also teaches about Adam and Eve right, so why do you rely on evidence? The fact that your beliefs rely on hardcore evidence of fossils, that is not even how faith is in Christianity or any religion. You believe in God Almighty, who is unseen, by faith rather than science. Thats what all religions are about, faith. Scientific miracles in the Quran tend to either open peoples eyes or they strengthn their already existing faith, but never does hard core scientific evidence serve as enough to fulfill ones faith. Rejecting faith because you dont have evidence infront of you is like rejecting God because he is not showing himself to you...Faith is way beyond that in both Christianity and Islam ;)
I hope that somewhat helped, if not then i guess our views on religion are just different which is okay. Feel free to further ask anything on this topic or others in the Quran :) I didnt talk about the bible and just gave you the Islamic view, but that would also be something interesting to discuss.