The answer is the quadricep muscles. They are engaged whe you use the leg extension machine.
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Repetition- bullies tend to repetitively bully the same victim.
Instead of using animals in medical expereince, i think<< that scientests could test it on bacteria or humans, if it is safe enough.
Answer:
Today, to benefit humankind, radiation is used in medicine, academics, and industry, as well as for generating electricity. In addition, radiation has useful applications in such areas as agriculture, archaeology (carbon dating), space exploration, law enforcement, geology (including mining), and many others.
Explanation:
By contracting, muscles pull on bones and allow the body to move.