Final answer:
Cygnus, Centaurus, and Cepheus are all examples of constellations, which are fixed patterns of stars in the sky named after mythological figures or apparent shapes, contrasting with the 'wandering' nature of planets.
Step-by-step explanation:
The examples given in the question, such as Cygnus, Centaurus, and Cepheus, are all constellations. A constellation is a group of stars that forms a recognizable pattern in the sky and has been named after its apparent form or identified with a mythological figure. These constellations are part of the 88 modern constellations recognized and used by astronomers to navigate and categorize celestial objects. In contrast to planets, which were known to the ancient Greeks as 'wanderers' because of their movement across the sky, constellations maintain fixed positions relative to each other and are used to assist in identifying stars and navigating the night sky. For example, Orion is a prominent constellation that includes well-known stars such as Betelgeuse and Rigel and is surrounded by other constellations, illustrating the interconnected nature of these stellar patterns. Therefore, the correct answer to the question is 'a) Constellations'.