Crayfish have muscles. They need them to move.
muscular and skeletal
The Muscular-Skeletal System.
Exoskeleton: Crayfish have a hard shell, and no bones. That makes crayfish invertebrates (no spine). Gills: Crayfish respire underwater through gills, where humans use lungs. The circulatory system is the second one, the reason for this being that crayfish have no blood vessels (and humans obviously do).
The nervous system.
the muscular and cardiovascular system.
the main organ of the muscular system is the muscles
The nervous system tells the muscular system what to do.
muscular system
yes
what is the risk factor of the muscular system
Your bones are part of your skeletal system, not muscular.
The skeletal system is the organ system that works most closely with the muscular system.