Question

define galaxy.....................and pulley​

Answer 1

Answer:

A galaxy is a huge collection of gas, dust, and billions of stars and their solar systems. A galaxy is held together by gravity. Our galaxy, the Milky Way, also has a supermassive black hole in the middle. When you look up at stars in the night sky, you're seeing other stars in the Milky Way.

A pulley is a wheel on an axle or shaft that is designed to support movement and change of direction of a taut cable or belt, or transfer of power between the shaft and cable or belt.

Answer 2

Answer:

There are four main categories of galaxies:-

• elliptical,
• spiral,
• barred spiral,
• and irregular.

These types of galaxies are further divided into subcategories while at the same time other types of galaxies exist based on their size and other unique features.

A pulley is a wheel on an axle or shaft that is designed to support movement and change of direction of a taut cable or belt, or transfer of power between the shaft and cable or belt.