Questions

BackTracking is used for solving N-Queens problem

The structural unit of compact bone is Osteons or Haverisan systems.

Now a days, printers we are using are called as laser printers. The speed of a laser printer is measured in PPM i.e, Pages Per Minute. 

Laser printing is an electrostatic digital printing process. It produces high-quality text and graphics by repeatedly passing a laser beam back and forth over a negatively charged cylinder called a "drum" to define a differentially charged image.

Compared to inkjet printers which use ink for printing laser printers are more expensive as they use toner which lasts for long.

Cl|Cl-C-CHO|Cl→Cannizzaro's ReactionNaOH Cl|Cl-C-COONa|Cl+ Cl|Cl-C-CH2 |21Cl-OH

Andromeda Galaxy is the galaxy named after Greek princess Andromeda.

Operating system software is that manages resources on a network.