N=N₀*2^(-t/T)
N₀=200 g
T=10 d
t=30 d
N=200*2^(-30/10)=25 g
25 g will remain
Answer:
compound light microscope
I believe the answer is Viva
The dark colored moths are beneficial in a polluted area because they have a lesser chance of being eaten since they blend into the trees polluted with soot.