In certain cities, too, traditional farms and other forms of urban farming - such as crops grown on rooftops or vacant lots - may only be 60 to 100 miles away, close enough to compete with vertical farms. Vertical-farming projects have sprouted up in several North American cities as well as in the Netherlands, Scandinavia, Germany, Korea, Japan, Abu Dhabi and Singapore among others.
Deoxygenated blood enters the right atrium through three major veins: the superior and inferior vena cava and the coronary sinus. The superior vena cava returns all of the blood to the heart from tissues superior to the heart in the head, neck, arms and upper thorax. Likewise, the inferior vena cava returns blood to the heart from tissues inferior to the heart, including the legs, abdomen and lower thorax.
Arteries carry blood away from the heart. Pulmonary arteries transport blood that has a low oxygen content from the right ventricle to the lungs. Systemic arteries transport oxygenated blood from the left ventricle to the body tissues.apillaries. Capillaries, the smallest and most numerous of the blood vessels, form the connection between the vessels that carry blood away from the heart (arteries) and the vessels that return blood to the heart (veins).