Question

when buildings collapse, it is extremely difficult to safely locate and rescue people trapped inside. victims may be wedged into small spaces, and unstable rubble could collapse on rescue workers. an alternative to human rescue workers may be robotic cockroaches. real cockroaches are protected by strong yet flexible exoskeletons. they can also flatten their bodies through tiny cracks. a robotics researcher from harvard university and a biomechanics expert from the university of california, berkeley, were inspired to create mini robots that have the same features. the roach robots can squeeze through small spaces and skitter over unstable environments. fitted with cameras and microphones, they could be used in disasters to locate victims. what is the main, or central, idea of the passage? it is dangerous to search inside collapsed buildings, but cockroach - like robots can go places where human searchers cant or shouldnt. inspired by the strength and quickness of cockroaches, researchers created robots with the same characteristics. cockroach - like robots can fit through small cracks and move through unstable rubble.

Explanation:

The passage first points out the danger of human rescue workers in collapsed buildings. Then it introduces that inspired by real cockroaches, researchers created roach - robots. These robots have features like being able to squeeze through small spaces (similar to cockroaches' ability to flatten through tiny cracks) and can be used in disasters (implied by the context of rescue in collapsed buildings). The first option combines the danger of human rescue (trapped people, unstable rubble) and the advantage of roach - robots (go to places humans can't or shouldn't) which covers the main idea. The second option only focuses on the inspiration and creation of robots, missing the context of the problem (dangerous rescue situation). The third option only mentions a part of the robot's features without relating it to the rescue context.

Answer:

It is dangerous to search inside collapsed buildings, but cockroach - like robots can go places where human searchers can't or shouldn't.