Which of the following is the best description of a nebula?
A.
a large cloud of dust and gas
B.
a dense cluster of billions of stars
C.
a single sun surrounded by planets and asteroids
D.
a large cloud of comets and asteroids surrounding a solar system
A. a large cloud of dust and gas
The best description of a nebula is option A. A nebula is a large cloud of dust and gas.
To determine the best description of a nebula, let's examine the options:
A. A large cloud of dust and gas.
A nebula is indeed a large cloud of dust and gas. This option accurately describes a nebula.
B. A dense cluster of billions of stars.
This description does not fit a nebula. A dense cluster of stars is more representative of a star cluster or a galaxy, rather than a nebula.
C. A single sun surrounded by planets and asteroids.
This description does not match a nebula. It is more characteristic of a star system, where a central star is orbited by planets and asteroids.
D. A large cloud of comets and asteroids surrounding a solar system.
This description does not align with a nebula either. It portrays the Oort Cloud, which is a hypothetical shell of comets and asteroids believed to surround the outer boundaries of our solar system, rather than a nebula.
Therefore, the best description of a nebula is A. A large cloud of dust and gas.