According to rounding rules for addition the sum of 27.1, 34.538, and 37.68 is

acid rain does not usually kill trees directly. instead, it is more likely to weaken the trees by damaging their leaves, limiting the nutrients available to them, or poisoning them with toxic substances slowly released from the soil. the main atmospheric pollutants that affect trees are nitrates and sulphates.

its first and third is your answer i did the qustion the fourth isnt right