With the LED illuminated, flip the direction of the LED on the breadboard (notch on top now), and then flip it back to its original position (notch on bottom). What does your observation tell you about diodes (and LEDs)?

Explanation:

The full form of LED is Light Emitting Diode. It is a semi conductor source of light which when electrons passes or flows through them, it emits light. In the semi conductor, the electrons recombine with the electron holes to release high amount of energy. This energy is called photon.

When the LED direction is flipped in the breadboard and back to the original position, the LEDs are forced to be grounded. They will not be able to function without being grounded.

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answer: the metamorphic rocks are formed when they are exposed to high pressure and high temperatures. this happens when one of the earth's plates comes in contact with the other plate by traveling in opposite directions, straight into each other or slipping under one another. the friction that is caused by this activity results in   melting of rocks and when it cools they are known as metamorphic rocks. this process needs a controlled amount of pressure and temperature otherwise it may turn into magma.