It all depends what theory it is most are supported by really good evidence but they just don't have all the evidence so it can't be proven a fact at that time
Ice caps so it would be D
Hope it helps :-)
The H+ concentration in the lake has increased as a result of the acid rain.
The original pH of the lake was 7, which mean the water is neutral, but due to the acid rain, it drops to 5. This means, that the water has become acidic and how have more hydrogen ion. The H+ concentration in the lake has 100 times compares with its original pH.