The second day of biological emergencies

42.

(1) joint head, joint fossa

(2) articular surface, i.e ligament

(3)C, articular cavity, E, articular cartilage

(4) elbow joint, shoulder joint and wrist joint

43

(1) trachea, balloon, lung

(2) the lungs. Double breathing. When flying, the excess heat in the body is dissipated, reducing the friction between internal organs.

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If you don't take my advice, you're really hopeless.