Linebacker.
4
The guards. Then, the tackles. Then, receivers.
I'm not sure what the question is if your talking about the position Tackle then there can be as many as four 2 offensive and 2 defensive, but if you are talking about the action of Tackling someone there is no set number
In American Football one tackles a player. In Association Football (soccer) one tackles the ball.
No. Football is more physical than basketball. The average force of impact of tackles in football is much stronger than than contact in basketball.
Linebacker.
Solo Tackles
yes
it's between the two defensive tackles
Dallas Cowboy Free Safety Barry Church has the most tackles in the league for a defensive back thru week 16 in the 2013 season. He has 127 combines tackles, with 100 solo tackles and 27 assists.
Tosh-0 - 2009 Football Player Tackles His Teammate 2-4 was released on: USA: 3 February 2010
Theres a lot. There can be 2 or more wide receivers. Theres always 2 guards and tackles. Sometimes 2 runningbacks and sometimes 2 tight ends. On defense there can be 2 safetys, linebackers, defensive ends (outside linebackers), tackles and cornerbacks