Habits are subconscious behavior patterns that people acquire by repeating an

action over and over. Research supports that it is difficult, but far from impossible,
to change undesirable habits. The first step in mastering a habit is recognizing that it
exists; the second step is replacing it with a more desirable habit. Being consistent
and patient in one's new routine is vital to success. One study tracked people
attempting to incorporate a healthy behavior, such as eating vegetables, into their
daily routine. The new behavior became second nature for the participants after an
average of sixty-six days.

Why does the author refer to a study showing it took a group an average of sixty-six
days to change a habit?
to help explain the step-by-step process by which people can change a habit
to demonstrate that a habit is a subconscious behavior pattern that a person might not even recognize
to emphasize that breaking a habit is a time-consuming process of behavior modification

to provide evidence that changing a habit is difficult but possible with consistency and patience