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

[Q]: Passage: There are no forces of attraction or repulsion between gas particles . Attractive forces are responsible for particles of a real gas condensing together to form a liquid. It is assumed that the particles of an ideal gas have no such attractive forces. The motion of each particle is completely independent of the motion of all other particles. Answer: superscripts
[A]: Which measure indicates the number of electrons in a given sublevel?

[Q]: Passage: Solar energy travels in photons. Photons travel in waves, which make up electromagnetic radiation. Answer: photons
[A]: Solar energy travels in what?

[Q]: Passage: The ability to see is called vision. The brain and eyes work together to allow us to see. The eyes collect and focus visible light and change it to electrical signals that travel to the brain. The brain interprets the signals and "tells" us what we are seeing. Answer: brain and eyes
[A]:
What are the organs work together to allow us to see?