Question

a scientist claims that the ph of ocean water is decreasing as a result of increasing atmospheric co₂ concentration. is the information in the graph consistent with the claim and why?
no, because an increase in atmospheric concentration of co₂ would result in an increase in ph.
no, because an increase in atmospheric co₂ would result in a decrease of ocean co₂.
yes, because when atmospheric co₂ increases, more co₂ will dissolve in ocean water, forming carbonic acid which can cause a decrease in ph.
yes, because the ph is a measure of the ratio of the concentration of co₂ in the atmosphere to the concentration of co₂ in the ocean.

Explanation:

When atmospheric CO₂ increases, more CO₂ dissolves in ocean - water. CO₂ reacts with water to form carbonic acid ($H_2CO_3$), which dissociates to release hydrogen ions ($H^+$). An increase in $H^+$ concentration leads to a decrease in pH.

Answer:

C. Yes, because when atmospheric CO₂ increases, more CO₂ will dissolve in ocean water, forming carbonic acid which can cause a decrease in pH.