Questions

- Process management

- Main memory management

- File management

- I/O system management

- Secondary storage management

- Networking

- Protection system

- Command interpreter system

Good customer service means having thorough knowledge of your inventory, experience with your products, and being able to help customers make the best choices for them.

The logic in this puzzle is summing the result of [subtraction of upper two digits] & [addition of lower two digits] 

Hence, the result is  

(5 - 3) + (2 + 8) = 2 + 10 = 12.

Methane is the main component of biogas and natural gas.

Protons carry a positive electrical charge, electrons carry a negative electrical charge and neutrons carry no electrical charge at all. The protons and neutrons cluster together in the central part of the atom, called the nucleus, and the electrons 'orbit' the nucleus.

A Dice has 6 faces with 1 - 6 number of dots one on each side.

So in total 1 + 2 + 3 + 4 + 5 + 6 = 21 dots resembles as eyes.

Greek, demotic Egyptian and hieroglyphics.

Geysers are fountains of hot water and superheated steam that erupts with an explosion whereas hotsprings or thermal springs are found where water sinks deep enough the surface to be heated up by the interior forces and it comes out without any explosion. Iceland and New Zealand are the other countries having geysers while hot springs are relatively common.