Answer: False. It’s filled sand soaked in the blood of his enemies (and his own chakra).

Look at picture it gives it away 

 Gaara carries a giant gourd on his back filled with water to stay hydrated.

Reborn as a Vending Machine, I Now Wander the Dungeon

I Follow my friend to the basement everyday

Answer: True It happened in the classroom in Episode 3 after some pushed naruto to sasuke.