17. Jogging, dancing, lunges, brisk walking, squats and planking are examples of what FITT principle? a. Intensity b. Type c. Frequency 18. Which of the following is true about frequency? A. Effort level of the exercise Number of session in a week c. Period covered in an exercise session 19. What principle in physical activity is defined as gradual increase in exerting effort or load that is done not too slowly, nor too rapidly. a. Principle of Progression b. Principle of Overload c. Principle of Specifity 20 Which nrincinle in physical activity claims that in order to progress and improve our​