During the formation of a tornado, cool air condenses warm air evaporates cool and warm air sink cool and warm air meet

Option (4)

Explanation: For the formation of a tornado, warm air must meet the cold air.

Initially, the warm air present in the lower atmosphere, gets heated up, being less dense, rises up and mixes up with the cold and denser air mass present in the upper atmosphere. Due to this collision of both the air masses, and the presence of water vapor, it gets converted into water droplets and formation of clouds. With time a more intense funnel forms due to the wind from all direction and forms a tornado.

Thus, the correct answer is option (4).

it had to transfer to a care and maintenance mode

  the   balanced   equation   for   reaction of   ca metal   with   o2 to   produce   cao   is as below

2 ca+ o2→ 2 cao2

  explanation

the reaction is   balanced     since the   number of atoms   in reactant side is   equal to   number of atoms   in   product side.   for   example   they   are 2   atom of   ca in   reactant   side   and   2   atoms of ca   in   the product side.

  the   process   is a   meet the   requirement   of   redox   reaction because :     calcium   is   oxidized   from   oxidation state 0   to 2+   while   oxygen   is reduced from   oxidation   state   0   to 2-