Why did dinosaurs become extinct while crocs didnt, and secondly why have they not changed in appearence?

Question

they have apparently been around for 200 million years

Answer 1

its called natural selection.  the creatures best fitted to survive did. the first mammals lived with dinosaurs, they were naturaly selected to live. crocodiles are so perfectly made to survive in their habitat it is unessisary for them to change. although they went through the big change in size. 75 million years ago crocs were 50 ft long.

we to as humans will die from natural selection, once the world pop reaches 12 billion we will be in a downward decline under 1 billion peopel till it levels of again, and that will take a decade to happen about 2 decades till we reach 12 billion.

so we to will go through natural selection and only the most fit to survive will