Here's why:

* Conglomerates are composed of rounded gravel-sized fragments. These fragments can be made of various materials like rock, mineral, or even fossils.

* Organic sedimentary rocks are formed from the accumulation and compaction of the remains of once-living organisms. Examples include coal, limestone, and oil shale.

While a conglomerate might contain some fossil fragments, the overall rock is not formed primarily from organic material. It's classified as a clastic sedimentary rock, meaning it's formed from fragments of other rocks.