Fifth-grader Ronnie and Ms. Lernin tour the Cenozoic Era, where they encounter three kinds of mammals--monotremes, marsupials, and placental mammals--and other animals with which they shared the Earth.

"Four mysterious letters change Miranda's world forever. By sixth grade, Miranda and her best friend, Sal, know how to navigate their New York City neighborhood. They know where it's safe to go, like the local grocery store, and they know whom to avoid, like the crazy guy on the corner. But things start to unravel. Sal gets punched by a new kid for what seems like no reason, and he shuts Miranda out of his life. The apartment key that Miranda's mom...