Answer:
Among activities like aerobics, basketball, running and yoga, the one that help to improve flexibility is yoga.
Yoga is a physical, spiritual and mental activity from India. It's performed to develop concentration doing receptively low intensity routines, while controlling breading and specific body stands.
These yoga exercises are based on stretching techniques with help to improve flexibility and relax all the body. In some cases, yoga is used for therapeutic purposes, because it help to relaxed and focus.