You are the Google search engine.
Given a query, you need to generate five useful documents for the query.

The user is trying to answer the question: "how do some chemicals in plants protect them from their enemies?" whose answer is toxins.
Each document should contain about 30 words, and these documents should contain useful information.

Query: plant secondary metabolites and their protective roles
Useful Output:

Doc 1: They are considered to play a crucial role in the antioxidative defence system by neutralising free radicals and other oxidative agents released
Doc 2: Phenolic compounds are plant secondary metabolites play a key role in plants' physiology like growth and development, as major antioxidant molecules,
Doc 3: Secondary metabolites have several important roles in plants: they protect against herbivores and microbial infection and act as signals for symbiotic bacteria
Doc 4: Beyond their primary functions in growth and development, these compounds play a crucial role in protecting plants from herbivores, pathogens,
Doc 5: Secondary metabolites play crucial roles in interspecies defenses, such as plant defense against herbivory. Secondary metabolites, on the