It says in the Bible, that after Adam and Eve had Cain, Abel, and Seth, that they had other sons and DAUGHTERS... there you go! Because there were not many mistakes in DNA/genetics at that point, you could marry your sister. Consider the Panda bear, it has VERY sharp teeth, yet only eats plants. Animals, including dinosaurs, were originally created to eat plants... after Adam and Eve sinned, many of those same dinosaurs now DID eat meat, as did humans. But most dinosaurs, especially in their younger years, were only the size of sheep or dogs. The Bible says that GOD brought the animals to Noah. Two of every KIND, not two of EVERY animals. Two DOGS, not 2 wolves, 2 coyotes, 2 dingos, etc, just 2 DOGS. So, given the immense size of the ark and bringing on only 2 of every KIND of animals (young versions that would have lots of their lives ahead of them, but able to reproduce), there would be room on the ark for ALL of them. VERY INTELLIGENT!