Flexibility can be influenced by internal and external factors. in a paragraph, summarize which type of factor you feel is easier to control.

You should probably write your own paragraph. But here is what I would say...

The factor that is easier to control is the external factor. Externally, anything from the weather outside to the age of the performer can affect flexibility. General tissues and collagen change with age influencing the individual. Even basic things such as clothing and equipment can affect a performance. Dance surfaces and lack of proper shoes can also affect a performer's ability to perform at his/her best.

Hope this helps :)