Final Answer:
An example of a partial but sustained contraction of a whole muscle is maintaining posture or holding a specific position.
Step-by-step explanation:
A partial but sustained contraction of a whole muscle is referred to as muscle tone. Muscle tone involves a continuous and partial contraction of muscle fibers within a muscle even when it is not actively contracting. This phenomenon is crucial for maintaining posture, stability, and readiness for movement.
For instance, when you stand upright or sit, various muscles throughout your body are engaged in maintaining the position without causing overt movement. This sustained contraction helps stabilize joints and prevents the body from collapsing. It is an essential aspect of everyday activities and is particularly evident in activities requiring static positions, such as holding a yoga pose or maintaining an upright posture while standing or sitting.