You are planning a human-body unit and what you need is coverage. These seven meet each child at whatever level they are actually reading at. What this page does is tell you what each one covers and what it leaves out, so you can see the hole in your unit now rather than in week three. The skeleton is done properly by one of them. Digestion is done twice, once for the youngest in the room and once for the oldest. Two are whole-body tours and they are not interchangeable, because one is a read-aloud and one is a table reference nobody reads through. And one of the seven is honestly your book rather than a class text, which is worth knowing before you order thirty copies of anything.
Here is the coverage map, which is the thing a unit plan actually turns on. THE SKELETON: Steve Jenkins's Bones, and nothing else here comes close. He prints bones at life size and sets a human hand beside a bat's, so the children measure themselves against the page. It carries that part of the unit on its own. DIGESTION, TWICE: What Happens to a Hamburger? does it for the bottom of the class in short flat sentences with a cracker experiment they can taste, and Seymour Simon's Guts does the same journey for the top of the class in real photographs with sentences pitched around sixth grade. Those two are the same lesson at two levels, which is exactly what a mixed room needs. THE WHOLE-BODY TOURS, three of them, and they do different jobs. The Magic School Bus trip is the read-aloud that opens the unit: it covers digestion, blood, the heart, muscles and the brain inside one story, and it teaches while it entertains, so one copy in your hands does the work. Me and My Amazing Body is the floor of the room, the only thing here written for a child who is still learning to read at all. DK Eyewitness is a table reference, one spread per system, and it is the one people misbuy: nobody reads it through, so it wants two copies on a table and no expectations beyond that. THE OUTLIER: The Way We Work, which is dealt with below. WHAT THIS SET LEAVES OUT, and it is worth knowing before you plan. Bones and digestion are covered in depth and everything else is not. The heart and lungs, the muscles, the brain and the nerves, the senses and the immune system all appear only inside the three tours, at a spread or a page each. If your unit spends a full week on circulation, nothing here carries it and you will be writing that week yourself or finding an eighth book.