Any number of players may defend or attack at any time, except at penalty kicks (for defensive DFK fouls in the 18-yard box) and kicks from the penalty mark (tiebreaker used in tournaments requiring a clear winner). During those kicks, only the goalkeeper may defend, just as only one attacker may kick. Therefore, your answer is eleven during any time in the game other than PK or KftM.
It depends on the formation. Many teams play a 4-4-2 formation, meaning there are 4 defenders, 4 midfielders, and 2 forwards, while others may play 3-4-3 (same order of numbers). In reality, the Laws of the Game do not specify how many defenders a team must field, or that there needs to be any at all. The only position that the Laws require is goalkeeper; everyone else is an outfield player, and the coaches (or captains) can decide where they will be, what they will be called, and what their job is.
No usually the team has four defenders.
Yes. It can be a very fast game and players are trying to get into good positions and get past defenders if they are trying to score, or trying to keep close to strikers if they are defenders. So there is a lot of movement in a good soccer match. Players need to be fit to play it at the top level.
3
Yes.
there are on a soccer field 11 players. There are many different formations for soccer like 3 strikers, 4 mid-fielders, and 3 defenders and a goalie
3
one
Well 90 minutes in a soccer match 60 seconds in a minute. 90*60=5400 seconds
The four defenders stand in front of the goalkeeper. and prevent goals being scored. or steal the ball
3
The usual number is 4, but other regular formations include 5 defenders or 3 defenders. But in football you could in theory have as many defenders as you want! (As long as there are only eleven players) but it wouldn't be very tactical!
This is a very wide open question and depends on what type of soccer match but in a important Champions League match they would use around 20 cameras