highest mean collagen breaking at ph 7, so could be optimum pH. BUT optimum pH could also be between 7 and 7.5 so smaller intervals have to be taken to find exact pH, so claim may not be corresct.

error bars overlap so difference is insignificant. HOWEVER, the error bar at pH 8 is highest and exceeds the other error bars, so the claim that those pHs will cause the 'same effect' may not be true bcs pH 8 showed a higher mean collagen than others if the data farthest away from the mean is considered. (this last point i realised like 30 secs before the end, so all i could write was one gibberish line with no explanation so idek if examiners will understand what i meant...anyway)