Let's first think what could be a "positive" impact - this would mean making the environment more clean and more friendly towards other species.
So they could clean up the environment (from the mess that was likely introduced by a human activity) and support other organisms in it - for example by removing the physical barriers for migration of other species (bridges over the streets for example) <span />
I think this refers to the Soviet Union in WW2: It was almost taken by the Nazis in the time from October 1941 until February 1942, but it wasn't and it later took Berlin at the end of the War.
its your own opinion if you are wondering
In the first half of the 1800s, the arrival of large numbers of immigrants affect economic conditions in US cities because there were fewer jobs available.
Answer: Option B
<u>Explanation:</u>
During the end of the 1800, a large number of people from all parts of the world decided to leave their home land and shift to the United States which had adverse effects on this country.
This led to the deficiency and reduction in the availability of land and jobs available and also led to the failure of crops. There also came a situation of famine in that country.
