That is true because that’s where it’s mostly are
The rules of base pairing explain the phenomenon that whatever the amount of adenine (A) in the DNA of an organism, the amount of thymine (T) is the same (Chargaff's rule). Similarly, whatever the amount of guanine (G), the amount of cytosine (C) is the same.
Sediment pollution is the single most common source of pollution in U.S. waters. Approximately 30% is caused by natural erosion, and the remaining 70% is caused by human activity. ... Sediment pollution can have long-term impacts on aquatic insects, fish and other wildlife in affected waterways
C 9.0 103 cubic micrometer