What are the modifications that are observed in birds, that help them fly?

Excretion in the form of uric and urates in birds is helpful in

What helps the electrification of insulators?

Some dinosaurs had fathers althought they could not fly but birds have feathers that help them to fly. In the context of evolutin this means that

Air sacs of birds are helpful

What is the characteristic feature that is observed in seral communities during different stages succession?

What are the observations made in Rutherford a-particle experiment.

What are "nonsense codons" name them.

Three codons on mRNA are not recognized by transfer RNA. What are they? What is the general term used for them? What is their significance in protein synthesis?