UCS is a command that sets a new user coordinate system (UCS) by specifying points or by selecting an object. You can use the Object option to align the UCS with a selected object such as a line.

Based on 3 and 4, UCSBASE is a system variable that sets the name of the current UCS base. PLINEGEN is a system variable that controls how linetype patterns are generated around vertices. LWEIGHT is a command that sets the current lineweight, which is used for new objects and affects objects in the current space only.

https://knowledge.autodesk.com/support/autocad/learn-explore/caas/CloudHelp/cloudhelp/2016/ENU/AutoCAD-Core/files/GUID-0BE49DA1-B323-4758-B49B-4C497D194C7A-htm.html

https://knowledge.autodesk.com/support/autocad/learn-explore/caas/CloudHelp/cloudhelp/2020/ENU/AutoCAD-Core/files/GUID-E658D5E7-EE5C-4A06-BF34-F71CDB363A71-htm.html

To join multiple polylines into a single polyline, use the PEDIT command with the Multiple and Join options.

Initiate the PEDIT command:

Type PEDIT in the command line and press Enter.

Select Multiple option:

When prompted to select a polyline, type M for Multiple and press Enter.

Select all polylines:

Select all the polylines that need to be joined.

Use the Join option:

After selecting the polylines, type J for Join and press Enter.

AutoCAD will prompt for the fuzz distance. Press Enter to accept the default, which will join the polylines if their endpoints are within a small distance of each other.

Convert if necessary:

If the selected objects include lines or arcs that are not polylines, AutoCAD will ask if you want to convert them to polylines. Select Yes to convert and join them.

FalseYou cannot convert an arc to a line by hovering over the center grip of the arc segment. You need to convert the arc to a polyline first, then use the FLATTEN command, and answer YES to remove hidden lines. Then you can explode the polyline to get line segments. https://forums.autodesk.com/t5/autocad-forum/autocad-is-it-possible-to-convert-an-arc-to-a-segemented-line/td-p/2933624

Falseyou can edit the polyline width by hovering over certain grips if they are vertex grips or midpoint grips. However, if they are arc segment grips, you cannot edit the width by hovering over them1. Therefore, the statement is false. https://knowledge.autodesk.com/support/autocad/learn-explore/caas/CloudHelp/cloudhelp/2015/ENU/AutoCAD-Core/files/GUID-2070C02C-E18A-4333-BDC4-240F49F1C102-htm.html

Falseyou can add a new vertex by hovering over certain grips if they are edge grips or midpoint grips. However, if they are vertex grips or arc segment grips, you cannot add a new vertex by hovering over them2. Therefore, the statement is false.

Access the Add Scale Dialog:

Open the 'Edit Drawing Scales' dialog by clicking on the scale list in the status bar or through the SCALELISTEDIT command.

Add a New Scale:

Click on the Add button to open the 'Add Scale' dialog.

In the 'Add Scale' dialog, you will need to specify the drawing units and paper units for the new scale.

Enter the Required Scale Values:

For a scale of 1" = 120', set the Drawing Units to 1 and the Paper Units to 120.

This configuration means that 1 unit in the drawing will represent 120 units on paper, matching the desired scale.

Save the New Scale:

Click OK to save the new scale to the scale list.

The new scale of 1" = 120' will now be available for use in the drawing.

References:

AutoCAD Documentation on adding scales: Adding Scales

According to the AutoCAD for Design and Drafting documents, the CHAMFER command creates a beveled corner between two lines, while the FILLET command creates a rounded corner between two lines. Both commands can be used with the Polyline option to apply chamfers or fillets to all corners of a 2D polyline1. However, in this case, the lines are not polylines but separate line segments. Therefore, using the Polyline option will not work. Instead, you can use the Multiple option to chamfer or fillet multiple sets of lines without restarting the command2.

The object property that you should use when using the Insert Field command to generate the viewport scale, if the default scale list is being used, is the "Standard scale".

The "Standard scale" property is used to specify the standard scale factor for the viewports. It represents a value in the format of 1:n, where n is the scale factor. For example, if you set the standard scale to 1:50, the viewport will display objects at a scale of 50 units per drawing unit.

To use this property in the Insert Field command, you can select "Object" in the "Field category" dropdown and "Standard scale" from the "Field names" dropdown. This will insert a field code that will automatically update the viewport scale based on the properties of the viewport.

associative dimensions adjust to changes in the geometric objects they measure. Dimension associativity defines the relationship between geometric objects and the dimensions that give their distance and angles.

Based on 2 and 3, dimensions in a layout may be associated to objects in model space when the DIMASSOC system variable is set to 2.