instruction:
Given a scientific passage and an answer, generate a question for the given answer.
question:
Passage: The angle of reflection equals the angle of incidence. A mirror has a smooth surface and reflects light at specific angles. Light is diffused when it reflects from a rough surface. Mirror images can be photographed and videotaped by instruments. Answer: rough surfaces
answer:
What kind of surface would cause diffusion when light is reflected off of it?

question:
Passage: The lungs of mammals are unique in having alveoli. These are tiny, sac-like structures. Each alveolus is surrounded by a network of very small blood vessels (see Figure below ). Because there are millions of alveoli in each lung, they greatly increase the surface area for gas exchange between the lungs and bloodstream. Human lungs, for example, contain about 300 million alveoli. They give the lungs a total surface area for gas exchange of up to 90 square meters (968 square feet). That's about as much surface area as one side of a volleyball court!. Answer: alveoli
answer:
What in mammalian lungs, increases the surface area for gas exchange?

question:
Passage: Electrical energy is useful to us mostly because it is easy to transport and can be easily converted to or from other forms of energy. Of course, conversion involves wast, typically as heat. Answer: electrical
answer:
What type of energy is useful to humans because it's ease of transport and conversion to other forms of energy?