Fresh water animals are unable to survive for long in sea water. Given reason.

Explanation

**Step-by-Step Solution:**

1. **Understanding Osmosis**: Osmosis is the movement of water across a semi-permeable membrane from an area of lower solute concentration to an area of higher solute concentration. Freshwater animals have a higher salt concentration in their bodies compared to the surrounding freshwater.

2. **Freshwater Environment**: In freshwater, the concentration of salts (solute) is lower than that inside the bodies of freshwater animals. This creates a hypotonic environment for these animals, causing water to flow into their bodies through osmosis.

3. **Transition to Seawater**: When freshwater animals are placed in seawater, the situation changes dramatically. Seawater has a much higher salt concentration compared to the body fluids of freshwater animals.

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