Write profusely on the importance of algea to the economy

If u meant algae,

Algae form organic food molecules from carbon dioxide and water through the process of photosynthesis, in which they capture energy from sunlight. Similar to land plants, algae are at the base of the food chain, and, given that plants are virtually absent from the oceans, the existence of nearly all marine life—including whales, seals, fishes, turtles, shrimps, lobsters, clams, octopuses, sea stars, and worms—ultimately depends upon algae. In addition to making organic molecules, algae produce oxygen as a by-product of photosynthesis. Algae produce an estimated 30 to 50 percent of the net global oxygen available to humans and other terrestrial animals for respiration.
- https://www.britannica.com/science/algae/Ecological-and-commercial-importance