Crouching is bending or stooping down low to the ground. Crouching can be very similar to squatting.
The man in the picture is crouching down so he can take a photograph of something from a good angle.
Scientific name: genus: corvus
A crowd is a large group of people. Generally a crowd is a group of people with no particular order, jostling together.
You can also use crowd as a verb, as in "to crowd in together" which means putting a lot of things in a small space.
A crown is something that royalty and deities wear on their heads. Crowns are used to signify that the wearer is someone special, and might hold special power. Crowns are usually made from precious metal and are studded with jewels, but they can be also made from simpler materials like wood, flowers or leaves.