1. Skeletal muscle fibers do not have gap junctions, but heart muscle cells do. Why do you think there is this difference? In other words: Why would it be bad to connect skeletal muscle fibers with gap junctions?
2. What is the benefit of having gap junctions in the heart?

Gap junctions

Explanation:

Skeletal muscle also called as voluntary muscle, is anchored to bone by tendons and is used to effect skeletal movement in activities such as locomotion and maintaining postureMuscle associated with heart is called cardiac muscle is also an involuntary muscle but is more akin in structure to skeletal muscleBoth cardiac and skeletal muscles are striated, they contain sarcomeres and are packed into highly regular, repeating arrangements of bundlesSkeletal muscle do no have gap junctions because they are not single cellsThe gap junctions, which are protein-lined tunnels, allow direct transmission of the depolarizing current from cell to cell, across the chambers of the heart, so that the cells contract in unisonBecause of the way these gap junctions function, the cardiac muscle cells are said to be electrically coupled

A. mitochondrion b. nucleus