Question

in paragraph 9, what does the author mean by the phrase “early prototypes were mechanically primitive”?
early models of rescue robots were expensive to build.
early models of rescue robots were difficult to operate.
early models of rescue robots were large and awkward.
early models of rescue robots were simplistic in design.

Explanation:

The term "mechanically primitive" implies that the early prototypes had a basic or simple mechanical design. It does not refer to cost, operability, or size - awkwardness directly. Instead, it focuses on the simplicity of the design.

Answer:

Early models of rescue robots were simplistic in design.