Question

The flexion of the arm at the elbow by the biceps brachii and the extension of the arm at the elbow by the triceps brachii is an example of a(n) ________ muscle grouping.

Answer 1

The arm's bending and straightening at the elbow involve an antagonistic muscle pair comprising the contracting biceps brachii for flexion, and the relaxing triceps brachii for extension.

Step-by-step explanation:

The flexion of the arm at the elbow by the biceps brachii and the extension of the arm at the elbow by the triceps brachii is an example of a antagonistic muscle pair. This type of muscle grouping is essential in allowing controlled movement and maintaining joint stability. Muscles can only contract, not extend, so they operate in pairs where one muscle contracts to create movement, like the biceps during arm flexion, while the antagonist muscle, like the triceps during arm extension, relaxes. These paired muscles demonstrate the concept of muscle antagonism, typical of skeletal muscles, bones, and joints in humans and other vertebrates.