Please choose the correct ending to complete the given sentence: Education and Communications: [header] How to learn about igneous rocks [title] Recognize how igneous rock is made. [step] Igneous rock forms from magma (also called molten rock). Magma is a liquid that is under the earth.

Ending1: When the magma moves to a cooler part of the earth, it loses its heat and crystallizes into an igneous rock. [substeps] Magma is thick and is composed of very hot elements and compounds. Ending2: The heat from the magma maintains the formation of rocks. The outer layer is thick and is characterized by bark, but apart from that it isn't covered in any solid. Ending3: This is what the minerals use to heat the rock. To learn about igneous rock, look for information online. Ending4: It is pink when soft and calcium black when soft. [title] Choose igneous rocks for this method.

Answer format: ending1/ending2/ending3/ending4