Question

birds and dinosaurs
though we think of dinosaurs as being extinct, recent research suggests that their
modern relatives live among us in the form of birds. like birds, many dinosaurs built
nests, laid eggs, and had feathers. over the last twenty years, scientists have collected
more and more evidence suggesting that dinosaurs evolved into birds. for example,
thousands of fossils of dinosaurs with feathers have been found in china, and fossilized
dinosaur eggs are similar in size and shape to birds eggs. fossils have also revealed
information about dinosaurs skeletons. birds have hollow bones to enable flight, and so
did some dinosaurs. in addition, birds and dinosaurs exhibit many similarities in their
legs, feet, and claws.
what is the main, or central, idea of the passage?
fossil evidence shows that the legs, feet, and claws of dinosaurs and birds
are similar.
fossil evidence shows that dinosaurs and birds share many features,
suggesting that they are related.
fossil evidence shows that some dinosaurs had hollow bones, which probably
enabled them to fly.

Explanation:

The passage starts by stating that birds are modern relatives of dinosaurs. Then it gives multiple pieces of fossil evidence (feathers, eggs, hollow bones, similarities in legs - feet - claws) that show dinosaurs and birds share features. The first option only focuses on legs - feet - claws, which is too narrow. The third option only emphasizes hollow bones, also too narrow. The second option encompasses all the fossil evidence presented (many features) and the conclusion (related) that the passage builds towards.

Answer:

Fossil evidence shows that dinosaurs and birds share many features, suggesting that they are related.