Video Transcript
Which of the following rocks
contains small holes in its structure due to the extruding of gases during its
formation? (A) Granite, (B) sandstone, (C)
limestone, (D) basalt, (E) marble.
Rock is a naturally occurring solid
material substance formed from one or more minerals. Each type of rock can be grouped
into one of three classifications according to how it is formed.
Igneous rocks are formed when hot,
molten material cools. This hot, molten material is called
magma when it’s below the Earth’s surface and lava when it is above the surface. Magma has a high ambient
temperature and cools slowly, forming rocks with large crystals. The type of igneous rock formed
when magma cools slowly is called plutonic rock. Lava on Earth’s surface cools
quickly and produces rocks that contain small crystals. In addition, these rocks often
contain small holes caused by gases escaping or extruding from the lava. This type of igneous rock is called
volcanic or surface rock.
Sedimentary rock is formed when
layers of sediment or sand compact and cement together. When looking at sedimentary rock,
we can sometimes see the layers or even the individual grains of sand and sediment
that make up the rock.
Metamorphic rocks are often formed
when existing rocks deep underground come into contact with magma. The high temperature and high
pressure convert the existing rocks into metamorphic rocks.
In this question, we want to know
which of the rocks will contain small holes in its structure due to the extruding of
gases during its formation. This means that the rock is likely
a volcanic igneous rock. Let’s take a look at each of the
answer choices.
Granite is a coarse-grained
plutonic igneous rock that appears a combination of pink, white, gray, and
black.
Sandstone and limestone are
sedimentary rocks. Sandstone is a coarse yellow rock,
while limestone is a smooth, soft, white rock.
Basalt is a volcanic igneous
rock. It is primarily black and contains
lots of small holes.
Marble is a rough, white
metamorphic rock formed when limestone is exposed to high temperature and high
pressure.
We can see that the only rock that
is a volcanic igneous rock is basalt. Therefore, the rock that contains
small holes in its structure due to the extruding of gases during its formation is
answer choice (D), basalt.
