Why the swimmers can swim easily in water but not in Bog ?
Particle of matter have space between them. This space is more for gas and less for liquid. Or we can say the intermolecular forces are less in gas and more in liquid. Solids have strongest intermolecular forces. So one cannot cut the solid. Bog is a semisolid and have less intermolecular force of attraction. So a person is able to swim easily through water.