Who defines touching the line as being in or out in different sports?

Question

For example, when teh athlete or ball touches the line it means:

1. Football is in (both legs)

2. Tennis is in

3. Volleyball is in

4. Track and field is out

5. Basketball is out (3pt arc)

Answer 1

The international governing body for each sport usually maintains the rule book, making changes as needed or desired.  Hopefully for the good of the sport.  

Answer 2

Each sport has its own rulebook, and usually a competition committee which reviews the rules and sometimes implements proposed changes.