If you're meaning in season 1 when he is training for the saiyans, its 88 days (im pretty sure)
Several months.
Actually the kais are the strongest because they are the most powerful beings ever because who is the one who taught goku the spirit bomb that was used to kill kid buu. exactly my point the kais trained goku to be strong but trully the kais will always be stronger.
He was born with it. The Kais helped him grow it back in GT.
Goku's tail was removed by Kami in Dragonball. I believe one of the Kais regrew it in GT.
vegito is goku and vegeta fusion by the supreme kais earings
goku only died two times. He died when piccolo killed him with the special beam cannon when raditz came. and when he took cell to kais planet. he didnt die against frieza they thought he died when planet namek exploded but he found the ginyu force ship and it took him to the planet it had set to go to. and he didnt die against omega shenron in dbgt once they defeted him shenron appeared and said the dragon balls were overused so he said he would bring them back when the earth needed them. and goku rode off with him, goku wouldent return until the world needed him.
he originally from planet vegeta
after namek blew up goku went to a planet yardrat, to train, this is where he learned the instant transmission
Planet Vegeta
Goku because Frieza needed surgery to recover from planet Namek's explosion, which was caused by Goku
Goku ssj6 would win because Goku ssj1 can destroy the planet.
Goku wins by blowing up the planet luffy is standing on.