The correct answer is D. It consists of cardiac muscle tissues, which means it moves involuntarily.
The heart is termed as muscular organ which pumps blood in different animals through the vessels of blood which are found in the circulatory system.
Blood provides the body with nutrients and oxygen and removes the metabolic wastes.
Heart beats at 72 beats per minute. It is during exercise that the heart may increase its beats and when it is resting it lowers which is termed as normal and good for the health of the heart.
