Kallie wants to improve her tennis serve. she already practices every day the court is available, and her technique and energy output are outstanding. kallie should focus select one: a. frequency; performing more cardio-related workouts b. intensity; increasing the effort expended during her workout c. time; increasing the length of her workout d. type; performing a different activity to achieve her goal

Kallie should focus on the type; performing a different activity to achieve her goal (Option D)

Explanation: As Kallie is already giving a lot of time in practicing and her technique and energy output are outstanding, so her frequency, intensity and time in the FITT cycle are being completed.

She should focus on the type of activity she is performing. She should change it and see if it would make her tennis serve better.  

the suction machine and tubing is the equipment that should be left behind and should be most easily accessible.