Which feature of a typical professional networking site users add professional details to their profile ?

-Volunteer Experiences and Causes

-Skills and Expertise

-Sharing Bookmarklet

-Status Update

Skills and Expertise

Explanation:

-Volunteer Experiences and Causes  refers to unpaid work that people do with volunteer organization to contribute to society.

-Skills and Expertise  refers to talents and strengths people have to be able to perform a job.

-Sharing Bookmarklet  refers to a section in which people can share links or articles in their profile

-Status Update refers to a section that allows people to talk about their thoughts or share important information.

According to this, the feature of a typical professional networking site that helps users add professional details to their profile is skills and expertise.

only #2 represents an object at rest on a table.

in #1, there is no normal force due to the table; the object is accelerating downward.

in #3, the vertical forces are not balanced; the object is accelerating downward.

in #4, neither the vertical nor the horizontal forces are balanced. the object is accelerating upwards and to the right.