Given a scientific question, generate a correct answer to it.

Example Input: Overpopulation takes place when the number of organisms in an area exceeds what?
Example Output: carrying capacity

Example Input: What do you call a device that produces a very focused beam of visible light of just one wavelength and color?
Example Output: laser

Example Input: Four electron groups orient themselves into what shape that has four faces?
Example Output:
tetrahedron