Read this introductory paragraph, which is missing an important element. There was a time when robots and home automation were just a fantasy. Robots were found only in science fiction and home automation was limited to cartoon families who had every convenience at their fingertips. Meals arrived with a simple push of a button. A robot maid performed every task humans didn’t care to do. What is it missing?

A Thesis Statement.

Explanation:

An Introductory paragraph is one of the crucial elements of an effective essay as it primarily functions to grab the readers' attention(through a hook or topic sentence), reveal the author's claim or point of view(through a thesis statement), and provide necessary background information that would help the readers' in understanding the narrator's message effectively.

The given introductory paragraph includes a hook('there was..fantasy'), background information('Robots..fingertips'), and they together set the tone but it misses a crucial element i.e. 'thesis statement' which would help in revealing the key point or claim to the readers. It offers a summarized version of the key argument of the essay that the author is going to deal with and since it is missing, the author's point of view is not established.