The video tutorial introduces the basics of galaxies, explaining that a galaxy is a system of stars, gas, and dust held together by gravity. Galaxies are classified by shape into three main types: irregular, spiral, and elliptical. Irregular galaxies lack a defined shape and contain young stars due to abundant gas and dust. Spiral galaxies, like the Milky Way, have a disc shape with spiral arms and contain stars of various ages. Elliptical galaxies are spherical or oval, lacking spiral arms, and contain the oldest stars due to minimal gas and dust. The Hubble classification scheme is used to categorize galaxies based on their shapes.

What is a galaxy primarily composed of?

• Asteroids and comets

• Planets and moons

• Stars, gas, and dust

• Only stars

Which type of galaxy lacks a defined shape?

• Spiral galaxy

• Elliptical galaxy

• Irregular galaxy

• Barred spiral galaxy

What is a characteristic feature of spiral galaxies?

• They contain only young stars

• They have spiral arms extending from a central bulge

• They are spherical in shape

• They have no spiral arms

Which galaxy is our solar system a part of?

• Triangulum Galaxy

• Milky Way Galaxy

• Andromeda Galaxy

• Whirlpool Galaxy

What is a common feature of spiral galaxies?

• They contain only old stars

• They have a central bulge with spiral arms

• They are irregular in shape

• They lack gas and dust

What type of stars are predominantly found in elliptical galaxies?

• Young stars

• Middle-aged stars

• Old stars

• Newly formed stars

What is the shape of an elliptical galaxy?

• Disc-shaped

• Irregular

• Barred

• Spherical or oval

Which type of galaxy is known for having the oldest stars?

• Spiral galaxy

• Irregular galaxy

• Barred spiral galaxy

• Elliptical galaxy

What does the Hubble classification scheme categorize?

• Types of galaxies

• Types of stars

• Types of planets

• Types of nebulae

Which of the following is NOT a type of galaxy mentioned in the video?

• Elliptical galaxy

• Spiral galaxy

• Lenticular galaxy

• Irregular galaxy