there are billions of types of animals and insects, Noah could not have taken them all !
how many species of turtles are there? how many species of frogs are there etc... it's simple for you to say "he took 2 turtles" as it was when we learned the story when we were kids, but there are billions of species of each type of animals, and when I say species, I don't mean just 2 turtles with slightly different colors
no
when animals are from different species, they cannot breed(get married

) together
even if we build a huge ship today, with out technology, we do not have the ability to store 2 of each species of animals
that is one issue
the second issue, when these 2 animals got married and had a generation, how did these children of theirs populate the planet again? they married their brothers and sisters? how did Noah's family repopulate humans, did they marry each other too?
third issue, how did the pigeon find a green leave to bring it to the ship after God flooded the planet? how did trees grow back alone? shouldn't Noah had saved the trees? and if God did not flood the planet what was the reason behind rescuing the animals? and what was the point in building the ship, he could have just moved to another cityI leave the floor to you to answer