Red is the color at the end of the spectrum of visible light next to orange and opposite violet. Red color has a predominant light wavelength of roughly 620–740 nanometres. Red is one of the additive primary colors of visible light, along with green and blue, which in Red Green Blue (RGB) color systems are combined to create all the colors on a computer monitor or television screen. Red is also one of the subtractive primary colors, along with yellow and blue, of the RYB color space and traditional color wheel used by painters and artists. 

In nature, the red color of blood comes from hemoglobin, the iron-containing protein found in the red blood cells of all vertebrates. The red color of the Grand Canyon and other geological features is caused by hematite or red ochre, both forms of iron oxide. It also causes the red color of the planet Mars. The red sky at sunset and sunrise is caused by an optical effect known as Rayleigh scattering, which, when the sun is low or below the horizon, increases the red-wavelength light that reaches the eye. The color of autumn leaves is caused by pigments called anthocyanins, which are produced towards the end of summer, when the green chlorophyll is no longer produced. One to two percent of the human population has red hair; the color is produced by high levels of the reddish pigment pheomelanin (which also accounts for the red color of the lips) and relatively low levels of the dark pigment eumelanin. QUESTIONS:

Q1:
1. Where on the spectrum of visible light can red be found?
2. What is red's position on the spectrum of light we can see?
3. 
Q2:
1. How did the sunset happen?
2. What made the sun go down?
3. 
Q3:
1. What percent of humans are redheads?
2. What percentage of people have red hair?
3. 
Q4:
1. Do the primary colors include red?
2. State if red is one of the primary colors?
3. 
Q5:
1. What are the other primary colors besides red?
2. What colors make up the primary colors with red?
3. 
Q6:
1. Who made use of the color chart?
2. Who was the color chart useful for?
3. 
Q7:
1. Does the sun set above the horizon?
2. Does the sun go down upwards of the horizon?
3. 
