The 21st Century Junior Library introduces young readers to important core content. Simple activities encourage students to Look, Think, Make a Guess, Ask Questions, and Create. The combination of reading and inquiring helps them develop the skills needed to master content and learn and succeed in the 21st century. Read all of these 21st Century Junior Library titles to learn about Which Is Which?: Aardvark or Anteater, Alpaca or Llama, Butterfly or Moth, Crocodile or Alligator, Frog or Toad, Porpoise or Dolphin, Seal or Sea Lion, Wasp or Bee