Answer the following question given this paragraph: 

Recall that terrestrial biomes are defined by their climate. That's because plants and animals are adapted for certain amounts of temperature and moisture. However, would aquatic biomes be classified in the same way? No, that wouldn't make much sense—all parts of an aquatic environment have plenty of water. Aquatic biomes can be generally classified based on the amount of salt in the water. Freshwater biomes have less than 1% salt and are typical of ponds and lakes, streams and rivers, and wetlands. Marine biomes have more salt and are characteristic of the oceans, coral reefs, and estuaries.


Q: How are aquatic biomes often classified?


A:
amount of salt