An element has three isotopes: St-284 (34.60%), St-285 (21.20%), and St-288 (44.20%). What is its average atomic mass?

I believe that it’ll be 284.45

Explanation:

May have to double check but I’m pretty sure that’s correct sorry if it’s not

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.

the answer is a and have a great day