Population is based on the de facto definition of population, which counts all residents regardless of legal status or citizenship--except for refugees not permanently settled in the country of asylum, who are generally considered part of the population of their country of origin.
The brain is made up of over 100 billion nerve cells with each brain cell connected to around 10,000 other cells, which equals around 1000 trillion connections in your brain. Your brain is actually very soft, jelly-like, and not grey but a deep red in color. The brain controls both involuntary, or lower, actions, such as heart rate, respiration, and digestion. Complex, or higher, mental activity, such as thought, reason, and abstraction, is consciously controlled.
What is color blindness? Color blindness means that you have trouble seeing red, green, or blue or a mix of these colors. It's rare that a person sees no color at all. Color blindness is also called a color vision problem. A color vision problem can change your life. It may make it harder to learn and read, and you may not be able to have certain careers. But children and adults with color vision problems can learn to make up for their problems seeing color. What causes color blindness? Most color vision problems are inherited and are present at birth. People usually have three types of cone cells in the eye.