Final answer:
Water moves from outside to inside an animal's tissues via osmosis because the surrounding water has a lower salt concentration and a higher water concentration than the animal's body fluids.
Step-by-step explanation:
If an animal has body fluids that have a higher salt content than the surrounding water, water will pass through the animal's body tissues from outside to inside because of the process known as osmosis. Osmosis is the movement of water across a semi-permeable membrane from an area of higher water concentration to an area of lower water concentration. In this scenario, the water surrounding the animal is less salty and therefore has a higher concentration of water compared to the body fluids of the animal. As a result, water moves into the animal to balance the concentrations, which can lead to issues with tonicity and water regulation within the organism.