Answer: By reading and revising the literature based on phenomenon or by performing an experiment.
Step-by-step explanation:
Essential questions are those key questions that can be asked from the students or the students can ask those questions after the lecture about a specific topic. The essential questions are asked by the teachers to determine the focus of the students on the lecture and how much information they have retained. This helps in improving the explanation ability of students. The essential questions are related to the phenomenon and it can be answered and find by recollecting what has been taught by the teacher, reading and revising the literature related to the phenomenon. These can also be answered by performing a scientific experiment.