This is the 3269th most frequent Russian word.
определяет
"Defines" or "determines."
In this sentence, 'определяет' means 'determines', signifying the direct influence or defining factor of teamwork on the project's success.
Умение работать в команде определяет успех проекта.
The ability to work in a team determines the success of the project.
Here, 'определяет' means 'chooses' or 'sets', indicating a decision-making process by the teacher regarding the lesson's topic.
Учитель определяет тему урока заранее.
The teacher determines the lesson's topic in advance.
In this context, 'определяет' means 'defines', expressing how the scientific approach establishes the framework or specifics of the method.