Germs are always present in our bodies. However, a healthy immune system keeps them at bay and fights off illnesses that do grow in our bodies. Perhaps the most important body system, the immune syste
Being active is essential to keeping the heart and lungs healthy. Those two organs have a lot to do with the overall health of the body, and they need to be taken care of! Readers discover the intrica
Body growth begins at the cellular level. From the start of life to the growth spurts of teens, it’s the tiny, basic units of life that make everything people do possible. Much about our cells and DNA
Without bones and muscles, running and jumping wouldn’t be possible—and neither would just sitting or standing! The skeletal and muscular systems give the body shape and power. Readers learn these sim
The brain is the most important organ in the body, but there’s so much scientists still don’t know about it. Its main connection is to the nervous system, which helps it tell the rest of the body what
Digesting a meal takes the body hours! The process begins in the mouth with saliva and moves to the stomach, which is full of acid that outside of the body could do some serious harm. From burping to
Presents information about breathing, discussing the main organs of the body's respiratory system, their functions in inhaling and exhaling, the composition of air, and ways in which the lungs can be
Provides information about the heart and its role in moving blood around the body, discussing the size, location, and composition of the heart; what blood is for; giving blood; and how to keep the hea
