Why do icebergs float?

An iceberg floats in the seawater and some part of that iceberg is submerged. Find how much of the iceberg is submerged.

(Density of ice is $0.9 \mathrm{g} {\mathrm{cm}}^{-3}$, density of seawater is $1.1 \mathrm{g} {\mathrm{cm}}^{-3}$)

_____ is the upward thrust on an object by a fluid.

(Choose from the following: Buoyancy/ Atmospheric pressure)

The center of _____ is the point where the total buoyant force or upthrust due to the fluid displaced by the immersed part of the body acts.

(mass / buoyancy)