Answer:
20
Explanation:
number of protons+ number of neutrons= mass of atom
19+n=39
n=39-19=20
number of neutrons=20
The elimination of an organism in an ecosystem takes out all balance. There may be an overpopulation of some organisms, and an underpopulation of others. For an example, if rabbits were taken out of the food chain, there would be an overpopulation of grass, and underpopulation of what eats rabbits.
1in because it is a desert
c.polluting a river because u are contaminating the water
