Here's why:

* Organic debris refers to the remains of once-living organisms like plants and animals.

* Sedimentary rocks are formed from the accumulation and cementation of sediments, which can include organic debris.

There are several types of sedimentary rocks that contain organic debris, including:

* Coal: Formed from the accumulation of plant matter over millions of years.

* Oil shale: Contains kerogen, a solid mixture of organic compounds that can be converted into oil and natural gas.

* Fossiliferous limestone: Limestone containing the fossilized remains of organisms.

Note: While organic debris is common in sedimentary rocks, not all sedimentary rocks contain it.