Question

which opening sentence uses a question to grab the readers attention for an essay on \the effects of studying everyday\?
to study means to devote time and attention to acquiring knowledge.
most people study before they take a test.
have you ever wondered what would happen to your brain if you studied everyday?
studying is boring.

Explanation:

The task is to find an opening - sentence in the form of a question for an essay on "the effects of studying everyday". The first two options are statements about studying, the fourth is a statement about studying being boring. Only the third option "Have you ever wondered what would happen to your brain if you studied everyday?" is a question related to the effects of daily studying.

Answer:

Have you ever wondered what would happen to your brain if you studied everyday?