The algae at the beginning of food chain in figure 3-1 are?

The algae at the beginning of the food chain in Figure 3-1 are called primary producers. Primary producers are organisms that can make their own food from inorganic matter, such as carbon dioxide and water. Algae are a type of plant that can photosynthesize, which means they can use sunlight to convert carbon dioxide and water into glucose and oxygen. Glucose is a sugar that algae use for energy, and oxygen is a waste product of photosynthesis.

Primary producers are important because they are the foundation of the food chain. They provide food for primary consumers, which are animals that eat plants, such as herbivores. Primary consumers are then eaten by secondary consumers, which are animals that eat other animals, such as carnivores. And so on up the food chain.

In the figure, the algae are eaten by zooplankton, which are small animals that live in the water. Zooplankton are then eaten by fish, which are eaten by birds and other animals.