South Carolina READY 4th Grade Science Practice Test

Igneous rock is created from the cooling and solidification of molten rock, known as magma when it is beneath the Earth's surface and lava when it erupts onto the surface. When lava cools quickly, it forms igneous rock with smaller crystals, while slower cooling can lead to larger crystals. This process indicates that igneous rock is specifically the type formed from volcanic activity, making it the correct answer. The term "volcanic rock" refers to a type of igneous rock that specifically forms from lava, but it is more of a descriptor rather than a distinct category like igneous rock. Metamorphic rock is formed from existing rocks that undergo changes due to heat and pressure, and sedimentary rock is created from the accumulation and compaction of minerals and organic material over time. This further clarifies why igneous rock is the appropriate choice for the question regarding SAMPLErocks formed from cooled lava.