我的回答：

Adding layers from Arc GIS online into analysis.

How to activate a layer and make different layers in the same window.

The core elements of maps includes north arrows, scale bars, and legends.

We could find some useful information used in making maps form some websites likehttps://blogs.esri.com/esri/arcgis/category/mapping/andhttp://colorbrewer2.org

Basic maps should be clear and not confusing, for example, the color should show the meaningful information and have a clearcolor gradation.

某人的回答：

When exporting a map for printing or or to send to someone else, swtich the view of the map from data view to layout view. This will provide the audience with a map easy to read containing all of the common map elements

Data frames creates a mean to show different views of a map within the same document. Each new data frame created will show up in the layout view.

ArcGIS online provides easy access to datasets from other users and ESRI and allowsthe analyst to view a map in a document without having to download it.

There are 4 core map elements to incorporate in to your map to give it meaning and make it understandable. The four are Title, Legend (gives meaning to visible data), Scale Bar and North Arrow (shows size and direction). It is handy to include the map projections as well (uses for the map).

Symbology is important to consider when creating a map. Different styles of symbology show different meaning for the data. Single Symbols(illustrate the outlines of polygons), Categorical Symbology (groups attribute values together and gives them a color), Quantitative/Continuous Symbology (same as categorical except assigns color to ranges of value), Graphic and figure symbols give polygons a chart to show data.