instruction:
Given a scientific passage and an answer, generate a question for the given answer.
question:
Passage: Steel is an example of an alloy. An alloy is a mixture of a metal with one or more other elements. The other elements may be metals, nonmetals, or both. An alloy is a solid solution. It is formed by melting a metal and dissolving the other elements in it. The molten solution is then allowed to cool and harden. Several other examples of alloys and their uses are shown in Figure below . You can learn about an amazing alloy called memory wire at the URL below. If you have braces on your teeth, you may even have this alloy in your mouth!. Answer: an alloy
answer:
A mixture of a metal with one or more other elements is called?

question:
Passage: Waves are characterized by their ability to constructively and destructively interfere . Light waves which interfere with themselves after interaction with a small aperture or target are said to diffract . Answer: diffract
answer:
Light waves which interfere with themselves after interaction with a small aperture or target are said to what?

question:
Passage: 5.3 Functions of the Integumentary System The skin plays important roles in protection, sensing stimuli, thermoregulation, and vitamin D synthesis. It is the first layer of defense to prevent dehydration, infection, and injury to the rest of the body. Sweat glands in the skin allow the skin surface to cool when the body gets overheated. Thermoregulation is also accomplished by the dilation or constriction of heat-carrying blood vessels in the skin. Immune cells present among the skin layers patrol the areas to keep them free of foreign materials. Fat stores in the hypodermis aid in both thermoregulation and protection. Finally, the skin plays a role in the synthesis of vitamin D, which is necessary for our well-being but not easily available in natural foods. Answer: integumentary system
answer:
What system, which includes the skin, plays important roles in protection, sensing stimuli and thermoregulation?