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 Australian government estimates that 34.3 million kangaroos lived within the commercial harvest areas of Australia in 2011, up from 25.1 million one year earlier. As with the terms wallaroo and wallaby, kangaroo refers to a polyphyletic grouping of species. All three refer to members of the same taxonomic family, Macropodidae, and are distinguished according to size. The largest species in the family are called kangaroos and the smallest are generally called wallabies.