1. The brain controls the muscles that control breathing in and out.
Circulatory system
Nervous system
Digestive system
Respiratory system
2. The blood delivers oxygen to muscles, which they need to relax and contract.
Circulatory system
Musculoskeletal system
Excretory system
Respiratory system
Circulatory system
Nervous system
Digestive system
Respiratory system
2. The blood delivers oxygen to muscles, which they need to relax and contract.
Circulatory system
Musculoskeletal system
Excretory system
Respiratory system
Answers & Comments
Answer:
1.respiratory system
1.respiratory system 2.Circulatory system