This is the strongest intercellular connection between the functioonal units of life and it is important in cardiac muscle.

The correct answer for the question: This is the strongest intercellular connection between the functional units of life and it is important in cardiac muscle:, would be: intercalated discs.

Explanation:

Just like skeletal muscle fibers depend on T-Tubules to be able to propagate an electrical impulse between the sarcomeres that form it, so that all respond in syncronization, myocardial fibers also require to do this; otherwise the heart would simply not function. In the case of myocardium, the muscle of the heart, synchronization is vital in order for it to be able to pump blood and meet the needs of the body. Also, like skeletal muscle, these fibers count with a structure that will permit such a thing; intercalated discs. These discs are formed by the ends of myocardiocytes and extensions of plasma membrane, just like in T-Tubules and they play a vital role not just in unifying the entire muscle fiber, but also adjoining muscle fibers. They also play a vital role in action potential propagation.