Here are some books I think would make a nice addition to the Polar Biome Lessons:
Scholastic Polar Animals by Susan Hayes and Tory-Gordon Harris is well illustrated and easy to understand. It has a great overview of the Polar area and sections about the Arctic and Antarctic animals, plants and environment. It is a good book for younger readers with more illustrations than text.
Who Lives Here? Polar Animals by Deborah Hodge is an easy reader of 24 pages packed with fun facts and great illustrations about the polar regions’ animals.
Polar Worlds by Rosalyn Wade is for more advanced readers. It has details about both polar regions. The illustrations are excellent. It has sections about animals in the both areas of the poles. Also, it covers human activity in this frozen area.