Lava that hardens on the surface is called an extrusion. The rock layers below an extrusion are always older than the extrusion. ... There, the magma cools and hardens into a mass of igneous rock called an intrusion. An intrusion is always younger than the rock layers around and beneath it.
Answer:
Hi, there your complementary sequence will be
U-A-A-C
Explanation:
C i think i’m not sure tho
Answer: Stars?
Explanation: I think it is stars because there is only one star in our solar system. I don't know for sure if it is, but I think it is. Don't be too sure of my answer.