In what type of rocks would geologists most likely find evidence of past life forms?

igneous rocks
metamorphic rocks
volcanic rocks
sedimentary rocks

Geologist finds evidences of past life forms from sedimentary rocks. Sedimentation is a process in which mineral and organic compound settle in place. This description will tell you that the organic material from living organisms long time ago undergo the process of sedimentation resulting for their fossils to be found in sedimentary rocks.