Answer:
Muscles move body parts by contracting and then relaxing. Muscles can pull bones, but they can't push them back to the original position. So they work in pairs of flexors and extensors. The flexor contracts to bend a limb at a joint.
Explanation:
Answer:
The cells that make up the digestive, muscular, skeletal, reproductive, and excretory systems all need oxygen from the respiratory system to function, and the cells of the respiratory system as well as all the other system bneed nutrients and must get rid of metabolic wastes.
Explanation:
True...........................
Answer:
The tissues of multicellular, complex animals are four primary types: epithelial, connective, muscle, and nervous. Recall that tissues are groups of similar cells group of similar cells carrying out related functions.
Explanation:
.
