Answer: The statement that is not a determining factor in formation of intrusive igneous rocks is 'None of the above' and Magma cools very fast beneath the Earth's surface.
Explanation:
Rocks are naturally occurring solid materials that are made up of different types of minerals which affects it's texture and colours. The three main types of rocks are:
--> sedimentary rocks,
--> metamorphic rocks and
--> igneous rocks.
Igneous rocks are formed from the crystallization and solidification of hot molten rocks which originates from deep within the earth. Depending on where the molten rock solidifies, the igneous rock is divided into two, namely:
--> intrusive igneous rock and
--> extrusive igneous rock.
The INTRUSIVE IGNEOUS rocks are formed within or deep beneath the earth surface when the hot magma SLOWLY cools over millions of years until it solidifies. The slow cooling allows large crystals to grow.
Therefore the statements (None of the above and Magma cools very fast beneath the Earth's surface) are not a determining factor.