This is the 12366th most frequent French word.
étudiés
"Étudiés" means "studied."
In this sentence, 'étudiés' is used as a past participle modifying 'sujets' to describe the topics that have been examined or learned.
Les sujets étudiés cette année incluent la biologie et la chimie.
The subjects studied this year include biology and chemistry.
Here, 'étudiés' is again a past participle, but in this context, it is part of a verb tense construction (passé composé) used to express that the action of studying took place in the past.
Ils ont étudiés ensemble tous les soirs avant l'examen final.
They studied together every night before the final exam.
In this usage, 'étudiés' forms part of a passive voice construction indicating that the action of studying should be done regarding the concepts.