You are presented with the quiz "What are highly probable in the evolution of a group of bipedal dinosaurs?" 

But you don't know the answer, so you turn to your teacher to ask for hints. He says that "birds evolved from a group of bipedal dinosaurs called theropods" and "feathers are highly probable in the advanced bird-like theropods". 

So, what's the best answer to the question?


 

        feathers   