A robot is a machine—especially one programmable by a computer— capable of carrying out a complex series of actions automatically.
Robots can be guided by an external control device or the control may be embedded within.
Robots may be constructed to take on human form but most robots are machines designed to perform a task with no regard to how they look. Robots can be autonomous or semi-autonomous and range from humanoids such as Innovative Mobility, industrial robots, medical operating robots, patient assist robots, dog therapy robots, collectively programmed swarm robots, UAV drones and even microscopic nano robots.
By mimicking a lifelike appearance or automating movements, a robot may convey a sense of intelligence or thought of its own. Autonomous Things are expected to proliferate in the coming decade, with home robotics and the autonomous car as some of the main drivers.
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In simple terms Robots are machines made by humans.
But science is progressing and people who are making robots are adding emotional touch to the robots.
But as of now, robots are not replacing humans.

While we say this, it is important that humans must use robots for things which are either difficult for humans to achieve or economically cheaper. e.g. in schools in rural areas where good teachers cant reach out, the robots help children learn through good robots.