Answer:
A. A concept in geology that describes transitions and relationships among the tree main rock types.
D. A series of processes that create and transform the types of rocks in the Earth’s crust.
Explanation:
A and D are the best two answers from the choices below because they both correctly describe the rock cycle.
The rock cycle which according to Wikipedia is a basic concept in geology that describes transitions through geologic time among the three main types of rock;
1. Sedimentary,
2. Metamorphic and
3. Igneous rocks
A rock cycle can take very long time. It could be thousands or millions of years