What type of buildings and monuments are most susceptible to damage from acid precipitation?

The answer is those building made of limestone and marble. Structures with metal element such as iron are also susceptible.  Acid rain is mainly made of weak carbonic, nitric, and sulphuric acid that acts as weak acid of pH 5-6. The acid reacts with the calcium and carbonate elements in limestone and marble and erode the rock. These weak acids also corrode iron and make the metal weak.

this protocol provides a detailed procedure for co-immunoprecipitation (co-ip) to identify protein–protein interactions.

i think its the first one