Question

When lava cools underwater, ______ often forms.

a) pillow lava
b) pahoehoe
c) magma
d) aa

Answer 1

a) pillow lava

Pillow lava only forms underwater, and occurs when lava is squeezed out of a crevice and solidifies incredibly quickly.

Answer 2

When lava cools underwater, pillow lava often forms.

Step-by-step explanation:

• Pillow lava: These are the kinds of lava which can be seen as a pillow-shaped structure and the reason for the lava to take pillow shape is due to the extrusion of lava under water.

• These pillow lavas are usually known for basaltic composition, which means formation of rock through some cooling process. The size of the lava is depended upon felsic, the more felsic composition the larger the pillow and vice versa.