For one thing, could anyone from the medical profession say whether or not it is possible for a human being to live for over 900 years? If so, why has there never been any evidence found of ancestors who lived for hundreds of years?
Also, at the time of the flood the entire vegetation of the world was completely covered in salt water for months. The roots would have all rotted and there would be nothing left. How did all the plants grow back? How did all the thousands of species of insects survive on the ark? There was only limited space and surely they would have munched their way through all the fresh vegetation taken on board the ark in no time!
Except for the termites who would have had an adequate supply of food