Why are some of the geological time periods not represented in the strata forming the Grand Canyon?

A.) The age of some of the Grand Canyon's layers is unknown.

B.) Unconformities resulted in the erosion of some representative layers.

C.) During certain times of Earth's past, sedimentary layers were not forming.

D.) Most of the Grand Canyon's layers are made of igneous and metamorphic rocks.

B. Sometimes dirt will build up over millions of years and then there is a big flood and it all washes away. This creates a time Gap in the layers for those millions of years the dirt was there

Option: (D) -

"Most of the Grand Canyon's layers are made of igneous and metamorphic rocks."

Explanation:

Igneous and metamorphic rocks:

If we analyze the formation of the Grand Canyons it will stretch us back in times to more then 6 millions years ago in the Arizona State, US. As, the structure of the grand canyons show and represents more then just beauty and the artistic work of the natural phenomenons.

But, the over structure of the Grand Canyons is composed of the igneous and metamorphic rocks, as these materials can not hold any structures of the ancients animals and plants.

Because, the fossils are mainly found in the sedimentary rock which makes it easy for the researchers to study them with create technique.