On a new journey, Uncle Kuzya tells Chevostik about the structure of our body - about its most important systems and internal organs. How the processes of blood circulation, gas exchange and digestion occur. Why do we need a heart and lungs, a brain and a stomach, a liver and kidneys. How our muscles, eyes and ears work. Listening to Uncle Kuzya’s story, you will learn why the blood darkens, why people sweat, where we get energy from, how we feel soft and rough, cold and hot. And you will also find many, many more answers to children's questions that will make you wonder how interesting a person is! The book is intended for children of primary school age.