What are the three main differences between arteries and veins?
1. The blood vessels that are in charge of the transport of oxygenated blood from the heart is the arteries. The blood vessels that are in charge for returning the deoxygenated blood from the body to the heart for oxygenation, is the veins.
2. The other main difference between arteries and veins are their characteristics. Arteries are positioned deep within the muscle, their walls are thick, and it has a thick layer of internal muscle tissue. Meanwhile, the veins have narrow walls, located close to the body surface, and contains a thin layer of muscle tissue.
3. The artery carry the oxygenated blood down to the lower body, and the vein carry deoxygenated blood from the lower body to the heart and to the lungs to get oxygen.

How are arteries and veins similar?
The Arteries and veins are essential to the circulatory system. The artery gives oxygenated blood to the body while vein takes the deoxygenated back to the heart and lungs to supply blood.

Why are veins thinner than arteries?
Arteries carry blood from the heart to various organs of the body under high pressure so they have thick and elastic walls. Veins collect the blood from different organs and bring it back to the heart. The blood is no longer under pressure, so the walls are thin with valves to ensure that blood flows only in one direction.

Are veins bigger than arteries?
Arteries are thicker and stretchier to be able to handle the higher pressure of blood moving through them. Your veins are thinner and less stretchy. This structure helps veins move higher amounts of blood over a longer time than arteries. So no, veins are not bigger than arteries.

What are the two types of veins?
The two types of veins are the pulmonary and systemic veins. The pulmonary vein is to carry back the blood from the lungs to the heart. While systemic vein, carries the deoxygenated blood back to the heart.

Do veins have valves?
Veins are different from arteries because they sometimes also contain one-way valves that keep blood flowing in the right direction. These valves are especially important in your legs, where they help blood move up toward your heart.

References:
https://www.relainstitute.com/blog/what-is-the-difference-between-arteries-and-veins/
https://www.pw.live/exams/neet/difference-between-arteries-and-veins/
https://byjus.com/question-answer/why-do-veins-have-thin-walls-as-compared-to-arteries-1/
Veins: Anatomy and Function – Cleveland ClinicCleveland Clinic·https://my.clevelandclinic.org
https://www.ncbi.nlm.nih.gov/books/NBK470401/