It is Acid Rain since animal activity and plant groth are not types of chemical weathering definetely with frost wedging being physical weathering.
3 sf
<span>(Rules:
> Non-zero digits are always significant.
123 - 3sf
> Any zeros between two significant digits are significant.
102 - 3 sf
<span>> A final zero or trailing zeros in the decimal portion ONLY are significant.
4500 - 2 sf
0.04 - 1 sf
0.0013 - 2 sf )
</span></span>
