Ostras, or oysters, are marine mollusks found in both saltwater and freshwater environments. They have a hard, irregular shell that protects their soft body inside. Oysters are known for their ability to filter water, which helps maintain healthy aquatic ecosystems. They are also a popular seafood delicacy enjoyed raw, cooked, or in various dishes. In addition to their culinary uses, oysters play a significant role in the environment. They form reefs that provide habitat for other marine life and help stabilize shorelines. Furthermore, oysters are often cultivated in aquaculture, contributing to local economies and sustainable seafood practices.