Final answer:
Sea plants, such as algae and sea grass, undergo photosynthesis by using sunlight, carbon dioxide, and water to create glucose and release oxygen as a byproduct.
Step-by-step explanation:
In photosynthesis, sea plants, which include algae and sea grass, use sunlight, carbon dioxide, and water to create glucose, a carbohydrate, and release oxygen as a byproduct. Sea plants have specialized organelles called chloroplasts where photosynthesis takes place. These chloroplasts contain chlorophyll, a pigment that absorbs sunlight and converts it into chemical energy for the plant.