The Body Book by Shelley Rotner is one of my favorite nonfiction books for my toddler. We’ve checked it out a few times. It shows photos of children at all different ages, and it shows them engaging in fun outdoor activities with their feet, hands, legs, heads, eyes, noses.
This is not a boring anatomy book, and it doesn’t have too many words or descriptions. It just focuses on all the great things a kid can do with his body: it makes me want to run around outside on a sunny day!