Question

The universe consists of:
A. Galaxies
B. Planets
C. Stars
D. All of the above.

Answer 1

Hint: The universe is unimaginably and infinitely big commonly defined as the combination of everything that exists. It is composed of galaxies, planets, stars, asteroids, comets, meteors, etc.

Complete answer:
The Big-bang theory describes the expansion of the universe, an abundance of light elements, and the distribution of radiation. First is the expansion of space that is all the constituents of space are arranged in a metric spread over it. In this numerical system, a metric is expanding along with the universe and thus objects are moving. And hence the distance between the two objects is increasing proportionally.
Another feature is the presence of horizons which is the maximum distance from which light has traveled to the observer. And since, space is expanding, it limits the events in the future that we will be able to influence. This expansion creates the universe that we see today.
The universe is all the physical matters like stars, galaxies, planets, etc. present in space. Planets include mercury, Venus, earth, Mars, Jupiter, Saturn, Uranus, and Neptune. Examples of most abundant gases found in space are hydrogen, helium, and lastly oxygen. Stars are uncountable in number in our universe; the nearest star to our planet earth is a Sun.

The correct option is (D).

Additional information:
Between the vast space of the orbits of Mars and Jupiter, there are thousands of irregularly shaped lumps of rocks that orbit the sun. They are called Asteroids.
Meteoroids are chunks of matter which may originate from the asteroid belt.
Sometimes they may enter the earth’s atmosphere and burn up due to the heat generated by friction. These meteoroids which burn completely are called ‘meteors’.

Note:
1. The surrounding space includes everything from the earth to most parts of the space that can be called the universe.
2. The solar system, stars, and galaxies are parts of the universe.
3. The branch of science which deals with the study of heavenly bodies is called astronomy.