While doing fieldwork in Hawaii, you get the opportunity to witness firsthand a volcanic eruption. To get to the site of the eruption, you must hike a few miles over lava flows that erupted a few months earlier and are now cooled. You are walking on:

igenious rock

Explanation:

there are three types of rock sedimentary metomorphic and igenious, walking on lava that has cooled is igenious as igenious rocks are just lava that has cooled down

wow this is so hard for me im only in elementry school still!