Students explain that a body system has a special job and that all body systems work together.
Students describe some of the body's major systems and the organs they contain, and discover that tissues are made of cells. Students learn what the sun and planets are like and the position of each planet in our solar system. A sprouted seed is a simple system. Each part of the sprouted seed depends on other parts. For example, the roots of the sprout get water and minerals from the soil.