Questions

This is the reason why we see the same side of  the moon always

The given letter equation puzzle means that 

7 W of the W = 7 Wonders of the World.

Longest and shortest phases Of cell cycle:

Shortest Phase - M phase or Mitotic phase.

Longest phase - G1 phase of the Interphase

Longest and shortest phases During Mitosis:

Longest Phase - Prophase

Shortest Phase - Anaphase

An ignition safety switch is a safety device can shut off the engine if the operator falls off the PWC or out of the powerboat, or is otherwise thrown from the proper operating position.

How it works:

It allows the engine of the vehicle to shut off or to be turned off immediately as it is to prevent further complications to happen as this is being used when an emergency is launched

Where it is used:

Most powerboats and PWCs come equipped by the manufacturer with an emergency engine cut-off switch.