What is true of the origin part of a muscle?

The origin part of a muscle is indeed attached to the skeleton, which is why this choice is accurate. In anatomical terms, the origin refers to the fixed point of attachment of a muscle, typically located at a bone that does not move when the muscle contracts. This is essential for the muscle's function in producing movement in the body, as it provides a stable base from which the muscle can exert force.

Muscles commonly have two attachment points: the origin and the insertion. The origin is usually proximal, or closer to the body's center, while the insertion is distal and usually moves during the muscle's contraction. Understanding this concept helps differentiate the origin's role from that of the insertion, which is responsible for the muscle's primary action. In contrast, elements such as size or point of movement are not defining characteristics of the origin, making those alternatives less accurate in this context.