The document explains the muscular system's function, highlighting that muscles allow movement by pulling on bones. It emphasizes that muscles work in pairs, using the example of biceps contracting while triceps relax. This paired action is essential for movement.

1. Muscular
system

3. Contraction Relaxation
“Muscles pull the bones so we can move”

4. “Muscles work in pairs”
Ex: biceps and triceps
when the biceps
contracts the triceps
relax
How do muscles work?