Inside You, Around You, Can Drown You

Riddle:

I run through your veins, bead on your skin, and cover the Earth. I bring life, but too much of me takes it away. What am I?

Answer:

Water — It’s essential to life (in your body and the planet), appears as sweat, and fills oceans. But in excess, like in floods or drowning, it can kill. The riddle balances necessity and danger.