The blood is carried to the heart in blood vessels is named?

 Arteries:are blood vessels that carry blood away from the heart. All arteries, with the exception of the pulmonary and umbilical arteries, carry oxygenated blood.The human main arteries, part of the circulatory system.The circulatory system is extremely important for sustaining life. Its proper functioning is responsible for the delivery of oxygen and nutrients to all cells, as well as the removal of carbon dioxide and waste products, maintenance of optimum pH, and the mobility of the elements, proteins and cells of the immune system. In developed countries, the two leading causes of death, myocardial infarction and stroke each may directly result from an arterial system that has been slowly and progressively compromised by years of deterioration. 
Capillaries:are the smallest of a body's blood vessels, measuring 5-10 μm in diameter, which connect arterioles and venules, and enable the interchange of water, oxygen, carbon dioxide, and many other nutrient and waste chemical substances between blood and surrounding tissues. 
Veins:are blood vessels that carry blood toward the heart. Most veins carry deoxygenated blood from the tissues back to the heart; exceptions are the pulmonary and umbilical veins, both of which carry oxygenated blood. They differ from arteries in structure and function; for example, arteries are more muscular than veins and they carry blood away from the heart.

The veins are major blood vessels connected to your heart. The pulmonary veins carry oxygen-rich blood from the lungs to the left side of the heart so it can be pumped to the body. The superior and inferior vena cavae are large veins that carry oxygen-poor blood from the body back to the heart.

Confused on question what should we be answering

Neurotransmitters are messengers responsible for communication between neurons. they are released from synaptic vesicles and are received by receptors.  the communication is referred to as neurotransmission. the following statement is true about neurotransmitters: a. they're stored in synaptic vesicles in the axon.