Question

water flows in one direction. water contains less than one percent salt. fish, frogs, and insects live here. what am i? marine river ocean estuary

Explanation:

• Marine: Generally refers to salt - water environments like seas and oceans. Oceans have high salt content (about 3.5% on average), so the "less than one percent salt" description does not fit.
• River: Rivers are freshwater bodies (salt content less than 1%) with water flowing in one direction (from source to mouth). They are habitats for fish, frogs, and insects.
• Ocean: As mentioned, oceans have high salt content (around 3.5%) and do not match the "less than one percent salt" criterion.
• Estuary: Estuaries are areas where freshwater (from rivers) meets saltwater (from the ocean). The salt content in estuaries is variable and usually higher than 1% (it is a mix of freshwater and saltwater).

Answer:

B. River