Questions

DRDO stands for The Defence Research and Development Organisation.

The Defence Research and Development Organisation (DRDO) is an agency of the Republic of India, charged with the military's research and development, headquartered in New Delhi, India.

Here the puzzle follows the logic that

Right side number = sum of the number on the left side and the previous number on the left side

=> 6 = 4+2

=> 10 = 6+4

=> ? = 16+10 = 26.

The given statement, The heat from the sun reaches earth through Convection is FALSE.

Heat from the sun actually reaches the earth through Radiation. The process occurs through electromagnetic radiation, specifically, in which molecules are warmed when the heat reaches them, and these molecules then warm other molecules touching them, which continues until we feel the sun's heat.

I am Keyboard.

A Keyboard has keys of letters, space button and enter button.

The logic in the given puzzle is 

Addition of numeric values of corresponding letters in the first three figures gives respective corresponding letter in fourth figure. 

i.e, A = 1 , W = 23 , B = 2 => 2 + 1 + 23 =26 = 'Z'

Similarly, L = 12, K = 11 , A = 1 => 1 + 11 + 12 = 24 = 'X'

Here the missing letter is 'X'.