Final answer:
During a rising tide, water flows into the estuary as a flood tide, contributing to the mixing of fresh and salt water in these valuable estuarine environments.
Step-by-step explanation:
When the tide is rising in the ocean, water flows through an inlet that connects the ocean to an estuarine basin in a specific direction. This movement of water is known as a flood tide, and during this time, water flows into the estuary. The correct answer is c. Water flows into the estuary as a flood tide. Estuaries are biomes where the ocean meets fresh water, such as a river, resulting in both fresh water and salt water mixing to create brackish water. These areas are crucial for many aquatic organisms, particularly during the beginning stages of their life cycles, and the salinity levels influenced by tidal movements play an important role in their adaptations.