How does fish changes its density compared to humans?

To reduce its overall density, a fish fills the bladder with oxygen collected from the surrounding water via the gills. ... When the bladder is expanded, it displaces more water and so experiences a greater force of buoyancy. When the bladder is completely inflated, the fish has maximum volume and is pushed to the surface.

Explanation:

in the given question, the partial pressure is calculated by using the ideal gas equation, that is, pv = nrt

here, p is pressure, v is volume = 25 l, n is number of moles = 0.0104 moles, r is gas constant = -0.0821 l.atm / mol.k

t is temperature = 273 k

p = nrt / v

p = (0.0104 mol × 0.0821 l.atm / mol.k × 273 k) / 25 l

= 0.0093 atm