Question

what is the option used in inkscape to join more than one object​

Answer 1

Inkscape can Combine paths into a compound path ( Ctrl + K ) and Break Apart a compound path into separate paths ( Shift + Ctrl + K ). Try these commands on the above examples. Since an object can only have one fill and stroke, a new compound path gets the style of the first (lowest in z-order) object being combined

Answer 2

Answer:How to Merge Objects in Inkscape

Path > Combine. Let's say that you use the Ellipse tool to draw 2 overlapping circles. With both of them selected, you can try heading up to Path > Combine. ...

Path > Union. If we instead do a Path > Union on the 2 circles, we actually end up with one unified object. Which worked out much better for my cartoon eyes.

Explanation: