Answer :

The lungs and the heart work closely together. The lungs take in air and oxygenate the blood. The heart then pumps the oxygenated blood around tbe body. I hope this helps :)
kayt91

Musculoskeletal system: Muscular System and Skeletal System

when you flex a muscle it pulls on the bones.

our skeletal system is what keeps us upright and protects vital organs.

the muscles move the bones which allows us to move.