I want to know the answer to the following question:
Extra time has two periods which each are how long in minutes?
All the background I'm provided with is that "If the score is still tied after extra time, some competitions allow the use of penalty shootouts (known officially in the Laws of the Game as "kicks from the penalty mark") to determine which team will progress to the next stage of the tournament.". Is that enough to answer the question?
Answer: no