The largest animal alive today that is related to dinosaurs would be the saltwater crocodile.
The Dinosaurs,that's pretty obvious
the ostritch lays the biggest eggs today, but if dinosaurs were still alive they would lay the bigest eggs.
The ostrich lays the biggest but most dinosaurs laid bigger eggs than that.
No. There was no animal that vaguely resembled a human at all. Mammals that lived at the time of the dinosaurs were small, shrew-like animals :) But monkeys are awesome.
The blue whale, it is the largest animal that has ever lived.
Sauropod dinosaurs are the biggest land animals ever to have lived on Earth. However, the biggest animal ever is the blue whale. It can be up to 108 ft long and weigh 200 tons.
Probably a crocodile or a shark because they are related to dinosaurs.
Birds
No. Dinosaurs and alligators (crocodilians) are two separate groups of archosaurs. They are related but dinosaurs are not "advanced" alligators. And evolutionarily it makes no sense to say an animal "just developed."
Some dinosaurs started to have feathers, which evolved into the present day bird.
No, dinosaurs are more related to reptiles and birds.
Platypuses are not dinosaurs; nor are they related to dinosaurs.