Given a scientific passage and an answer, generate a question for the given answer.

Q: Passage: Bacteria called cyanobacteria are very important. They are bluish green in color (see Figure below ) because they contain chlorophyll. They make food through photosynthesis and release oxygen into the air. These bacteria were probably responsible for adding oxygen to the air on early Earth. This changed the planet's atmosphere. It also changed the direction of evolution. Ancient cyanobacteria also may have evolved into the chloroplasts of plant cells. Answer: chlorophyll

A: Cyanobacteria are bluish green in color because they contain what?
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Q: Passage: Conditioning is a way of learning that involves a reward or punishment. If you ever trained a dog to obey a command, you probably gave the dog a tasty treat each time he performed the desired behavior. It may not have been very long before the dog would reliably follow the command in order to get the treat. This is an example of conditioning that involves a reward. Answer: conditioning

A: The way of learning that involves reward and punishment is called?
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Q: Passage: Visible light is light that has wavelengths that can be detected by the human eye. The wavelength of visible light determines the color that the light appears. As you can see in the Figure below , light with the longest wavelength appears red, and light with the shortest wavelength appears violet. In between are all the other colors of light that we can see. Only seven main colors of light are actually represented in the diagram. Answer: wavelengths

A:
Visible light has what that can be detected by the human eye?
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