Remote Sensing refers to the use of aircraft or satellite-powered sensor technologies to identify and classify bodies on the Earth.

Here are the answers to your questions:

1. Remote Sensing refers to the use of aircraft or satellite-powered sensor technologies to identify and classify bodies on the Earth.

2. Electromagnetic radiation is used in all forms of remote sensing technology.

3. A pixel is the smallest individual unit of a digital image, representing a single point in a raster image and typically storing color or intensity information.

4. The energy source distinguishes between active and passive remote sensing. Active sensors provide their own energy, while passive sensors rely on naturally available energy (e.g., sunlight).

5. The visible, near-infrared (NIR), and shortwave infrared (SWIR) portions of the electromagnetic spectrum are relevant for optical remote sensing.

6. Two practical applications of remote sensing are land cover mapping and vegetation health monitoring.