The circulatory system of the human body is composed of many large and small blood vessels that transport blood throughout the body. The largest artery in the human body is the aorta. This blood vessel is responsible for pumping oxygenated blood from the left side of the heart to the head and body. The aorta is attached to the left ventricle of the heart.
Although there are many different species of both wallabies and kangaroos that span a wide range of sizes, wallabies only tend to weigh between four pounds and 53 pounds (2 kg to 24 kg) and grow a mere 12 inches to 24 inches (30 cm to 104 cm) tall, not including their tails [source: Wallaby].
The Kangaroo Family. Kangaroos belong to the superfamily Macropodoidea, which also includes wallabies. This superfamily has 62 members native to Australia and Papua New Guinea, ranging in size from those who weigh as little as 2 pounds to about 200 pounds. Six kangaroo species are the big boys of this family, although a new, and slightly smaller, kangaroo family member was discovered in Papua New Guinea in 1990. The wallaroo, a crossbreed of wallaby and kangaroo, is another relative.