Woman's indoor volleyball?

Question

why is there always someone with a different colour t shirt in each team

Answer 1

it's the libero the go into pass on back row and now they can serve this year. it distinguishes them from the other players on the court

Answer 2

There is a defensive specialist called the Libero.  They wear a different colored from the rest of the team and they must be clearly contrasting shirt from the rest of the team.  

The reason they wear a different shirt is that they are allowed to enter the back row for any back row player and then be replaced by that player and then go in for another player.  The  Libero replacements are not counted as substitutions and can happen on any dead ball.

Answer 3

They are called the libero.  They stay in the back row, and are also called defensive specialists.  they can't hit or set in front of the 10 foot line, either.  they wear different colored shirts because they are supposed to go for all the balls, diving or not, and people need to know where they are at all times, so it's easier to spot them when they are wearing different colored shirts.  It's also so they can stay in position easier.  hoped i helped :D