Out of the given statements, the statement that best describes the impact of a dam on the environment is that it causes changes in the river ecosystem.
<u>Explanation:</u>
Dams are usually built on rivers that flow through valleys formed by two elevated landforms on two sides.
Thus, when a dam is built, it interferes with the natural setting and stops the natural flow of the water.
This makes the water levels behind the dam grow considerably. Many a times, the landforms in the surrounding regions get submerged in the water due to the increased levels of water.
The natural movement of aquatic animals like fishes and crabs is also hindered by the dam.
ArcGIS software developed by Esri and launched in Dec 1999, used to create maps and compile geographic data.
For windows, its components include arc reader arc desktop, which includes ArcView, ArcMap, and other tools that are used to do spatial analysis. Again the arc desktop is divided into the basic, standard and advanced edition.
The arc desktop 8.1 released in 2001 was an application with GUI and included extensions like 3D, Spatial, and GeoStatistical Analyst. It used to store files as a DB file as a personal database. Arcgis often need a license file to run the program.
As compared to the Online Arcgis is an online web application used to sharing and searching for geographic information. Allowing users to create and join groups, and access items shared within groups.