Immigration followed by competition
I hope this right, if its not, sorry =)
The natural spreading of particles through a liquid or gas is called diffusion
Take India for example.... people use the bathroom and bathe in rivers!
Now lets say we look at the US our pollution comes from factories, trash that people dont throw away, fertilizers and many more... but the difference is, that in developed countries like the US our water is filtered.... And in India water is not safe to drink
Not sure but my best guess is to go with B. It just makes the most sense.
It is heated up to get rid of any killing germs that can harm you. Cows or any milk giving animal don’t always give bacteria free milk.
