Alava flow is an example of an igneous rock (one of the two main igneous rock groups).

The correct answer is Extrusive igneous rocks.

Explanation:

Extrusive igneous rocks also known as volcanic rocks form when magma reaches the Earth's surface in a volcano and cools rapidly.

This is the partial melting of the rocks inside the mantle and the crust.

They are smooth, fine-grained and crystalline. Its main effect is that magma cools much faster when it is outdoors or underwater, and this way, there is not much time left for crystal growth.