The West is blinking in disbelief â Vladimir Putin just invaded Ukraine. German diplomats, French Eurocrats and American pundits are all stunned.
The  circulatory system is the body's transport system. It is made up of a group of organs that transport blood throughout the body. The heart pumps the blood and the arteries and veins transport it. Oxygen-rich blood leaves the left side of the heart and enters the biggest artery, called the aorta.
The human brain is the central organ of the human nervous system. The human brain, with the spinal cord, makes up the central nervous system. The brain consists of the the cerebrum, its largest part, the brainstem and the cerebellum. The brain is the organ that controls most of the activities of the body.