Answer the following question given this paragraph: 

Ash and particles shoot many kilometers into the sky. The material may form a mushroom cloud, just like a nuclear explosion. Hot fragments of rock, called pyroclasts , fly up into the air at very high speeds. The pyroclasts cool in the atmosphere. Some ash may stay in the atmosphere for years. The ash may block out sunlight. This changes weather patterns and affects the temperature of the Earth. For a year or two after a large eruption, sunsets may be especially beautiful worldwide.


Q: What are hot fragments of rock called?

 Choices:

- obsidian

- magma

- shards

- pyroclasts

A:
pyroclasts
