Which one of the following is considered at the primary level in the food web?ans.Green plantsNostocHomo sapienceAnabina

In a food web, the primary level is typically occupied by producers, which are organisms that can make their own food through processes like photosynthesis. Let's analyze each option given:

1. Green plants: These are definitely producers, as they use sunlight to create their food through photosynthesis.

2. Nostoc: This is a genus of cyanobacteria, which also has the ability to photosynthesize, thus serving as a producer in aquatic environments.

3. Homo sapiens: This refers to humans, who are consumers in the food web, not producers.

4. Anabina: This is another genus of cyanobacteria, similar to Nostoc, that can also perform photosynthesis and act as a producer.

Conclusion:

The options "Green plants," "Nostoc," and "Anabina" are all considered at the primary level in the food web. However, "Green plants" is the most common and well-recognized example in ecological terms as the primary producers.

Final Answer:

Green plants are considered at the primary level in the food web.