Questions

A UPS (Uninterruptible Power Supply) is a device that provides battery backup when the electrical power fails or drops to an unacceptable voltage level.

Small UPS systems provide power for a few minutes; enough to power down the computer in an orderly manner, while larger systems have enough battery for several hours.

Sublimation is a process when a solid changes directly into gas instead changing into liquid first. Dry ice is an example of Sublimation process because it doesn't change into liquid CO2 and directly change into gaseous CO2 when heated.

Hence, Dry ice is an example of Sublimation process. 

Hubs are specified or operate at Layer1 i.e, the physical layer in the OSI model. Hubs regenerate electrical signals. A hub sends data packets (frames) to all devices on a network, regardless of any MAC addresses contained in the data packet.

Mt. Etna