The level of organization the student observed is community.
There are different levels of organization in Biology, more specifically Ecology, and these levels are listed below and explained in order from the highest to the lowest level.
The biosphere, which includes the largest part of the Earth, represents all living organisms on the land, in the ocean, and in the atmosphere.
An ecosystem is the next level of organization, which is a specific area with living organisms. It includes all the living organisms in that area but also the non-living environmental aspects, so it includes both biotic and abiotic factors.
A community includes all biotic factors of a specific area, so it is the biotic part of an ecosystem. This means that a community refers to all the populations of different species that live in a specific ecosystem and interact with each other.
A population is a level below a community, and above species, which refers to all of the individual organisms of one species that live in a specific community and interact with each other.
A species is a group of organisms that live in the same area, and interact with each other to breed, to produce viable offspring. All members of a species are genetically related and can be bred to produce fertile offspring.
Since the student in the example is observing a lake, which is an ecosystem, and he listed all the living organisms he found in that lake, we can conclude that the level of organization observed in the table is community. He described different shrimp species, and an insect species, and he didn't describe any abiotic factors, so that brings us to the level of community.
