Us history : (at least 3 sentences each < 3 )

1. why might historians need to describe different places on earth?

2. how have humans altered the landscape of the united states?

3. how does geography impact history? how do the physical and human features of an area impact the events that happen there?

2. The human have impacted the earth landscape in positive and negative ways. One example of a positive change is the way we recycle and do many projects to save the earth. One Negative way is that we build lots of building destroying the natural landscape, also taking over the animals habitats.
 

They have to enter the cell of another organism.