It takes 66 days for it to become a habit
The correct answer is internal.
Thoughts and feelings that people either share with others or choose not to share with them are internal because they happen within your mind and body, not outside of it. So in Perry's case, what he is feeling towards horseback riding is also internal because he is not expressing that overtly.
The correct answer is letter C
Explanation: Population Explosion the high population growth in the world or a specific territory or region. It can be caused by different reasons, varying according to the historical period and the different locations.