Which component is commonly described as providing the ability to sense the physical world in IoT?

• A. Heterogeneity
• B. Security
• C. Connectivity
• D. Sensors

Answer: (D)

Sensors are what let an IoT system sense the physical world. They measure phenomena such as temperature, humidity, light, pressure, motion, or biological signals, and translate those observations into electrical signals or digital data that a microcontroller or gateway can read. This sensing capability is what turns real-world events into information that can be monitored, analyzed, and acted upon—forming the bridge between the environment and the digital system. Other aspects like heterogeneity describe the variety of devices and data formats, security focuses on protecting data and devices, and connectivity handles transmitting data across networks. None of those by themselves sense the environment; sensing is the function of sensors.