Answer:A
Explanation:
it would be decrease in air pollution because that's a impact of beach use by humans and vehicles.
The period during which the presence of stromatolites decline is the Proterzoic period. Stromatolites are widely distributed sedimentary structures consisting of laminated carbonate or silicate rocks, produced over geologic time by the trapping, binding, or the precipitating of sediment by groups of microorganisms, primarily cyanobacteria.
Catalyst maybe ( lower activation energy).
