Most skeletal muscles are in pairs so that one muscle alternates with the other muscle to equalize the work load.
one muscle flexes (bends) and the other muscle extends.
one muscle does more work and the other muscle does less work.
one muscle uses more energy and the other muscle uses less energy.

One muscle flexes while the other extends

Explanation:

answer; philip zimbardo;

answer: b. complete secondary assessment (detailed physical exam).

after you finished the primary assessment, you must proceed with the assessment by performing a complete detailed physical examination.

this secondary assessment includes a focused on patient’s history, vital signs and a specific and rapid examination of the entire body especially on the injuries acquired from the motor vehicle accident and the patient’s medical complaint.