Holding your breath underwater is when your head/face is underwater and you do not breath.
Hippos can't "breath" underwater but they can hold their breath for long periods of time.
To do the underwater challenge in Peru, YOU HOLD YOUR BREATH UNDERWATER DUMMIES
No. Human beings cannot breath underwater at all without an external source of air.
they have gills.
You Can't At All
they don't.
I will assume you are not joking. A fish does not hold it's breath it can breathe underwater using its gills.
A whale CAN drown- they cannot stay underwater indefinitely. When underwater, they hold their breath. They are REALLY good at holding their breath, and their bodies have adapted to doing that.
how does a galapagos penguin breath
Um, with gills. . . ??
by drinking the water