One source that would provide relevant information would be information taken from the governor's website that promotes nutrition guidelines.
We can arrive at this answer because:
The term "-gov" refers to government websites. An example of this type of website is "Nutrition" which is the official website of the government to transmit coherent and correct information about the nutrition of citizens of all ages.
Therefore, this website would be a great option for researching an essay on school nutrition.
More information about research sources at the link:
https://brainly.com/question/15314748