Final answer:
Edible parts of algae include leaf-like blades of brown algae such as kelp, red algae like Porphyra, and green algae such as sea lettuce. Most large, multicellular algae, known commonly as seaweeds, are consumed for their nutrient-rich and low-calorie profiles.
Step-by-step explanation:
The edible parts of algae include various structures depending on the type of algae. For instance, large multicellular algae such as seaweeds, which are brown algae (Phaeophyta), are commonly consumed. Seaweeds like kelp (Laminaria) have leaf-like blades which are edible. Another example is Porphyra, a red algae, which is also consumed, particularly in Asian cuisines. Green algae such as the sea lettuce (Ulva) are frequently eaten as well. Algae provide a range of nutritional benefits and are incorporated into many products due to their nutrient-rich profiles. They are low in calories and high in vitamins and minerals, making them an attractive food source.