In this diagram, medium A represents water and medium B represents air. The phenomenon in this diagram, moving from A to B, is called

In this diagram, the phenomenon moving from medium A which represents water to medium B that represents air is called refraction.

Explanation:

Refraction takes place when light passes through a water surface due to its refractive index which is 1.33. Air possesses a refractive index of about 1. Looking at the phenomenon moving between medium A and B, it seems to bend at the water's surface. This happens because of the bending of the light rays as they move from the water to the air. The time when the rays reach the eyes, the eyes trace them back as straight lines or lines of sight. These lines divide at a higher position than where the actual rays originated. This causes the phenomenon to appear higher and the water to appear shallower than what it is in reality.

i believe it is-

d.) gravity pulled particles of dust and gas together to form planets.

  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-