The phrase that best describe the word "energy" is letter "C. the ability to do work". The unit most commonly used to express energy is Joules (J) which is also derived from the equation of work which is the product of force and the distance that a body moves parallel to the force applied.
Amoebas are single-celled organisms, which means that they are composed of just one cell. Each amoeba is a cell capable of performing all living functions by itself. They can reproduce asexually. They are protozoans with no fixed shape. Most have no hard parts and look like blobs of jelly.
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 posture
Muscle associated with heart is called cardiac muscle is also an involuntary muscle but is more akin in structure to skeletal muscle
Both cardiac and skeletal muscles are striated, they contain sarcomeres and are packed into highly regular, repeating arrangements of bundles
Skeletal muscle do no have gap junctions because they are not single cells
The 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 unison
Because of the way these gap junctions function, the cardiac muscle cells are said to be electrically coupled
