Need some more info:
What level is that class? High School, Com. college, University, Grad School
How much time do you have?
What is the specific assignment? Paper, Project, presentation, speech,
Ideas that could work at any levels:
Compare and contrast of plants grown in a poly culture vs. monoculture.
Benefits of no till approach.
Exploring the relationship between mycelium network and plant health.
Effects of biodiversity, or lack there of, on the ecosystem.
Mimicking natural succession through support species and chop and drop.
Permaculture is such a huge topic that you really have the information for breadth or depth of whatever you choose to pursue.