Concept:Sedimentary rocks form from the accumulation and compression of sediments in distinct layers.
Explanation:The most characteristic feature of sedimentary rocks is their layered structure, known as strata.
These layers are deposited one above another over time.
Sedimentary rocks are not generally crystalline in structure.
They also do not have high resistance to erosion compared to many igneous or metamorphic rocks.
Being basaltic in nature is a property of certain igneous rocks, not sedimentary rocks.
Therefore, the correct characteristic is that they are laid down in strata.
Answer:A. are laid down in strata