Well, just so you can remember, I'd like you to answer the following questions, if you please.
- What is a ninja?
- What is chakra?
- What are the basic five elements?
- What is ninjutsu?
- And, why do you want to learn ninjutsu and why?
Okay.
1; A ninja or shinobi, us someone apart of a village, expected to be loyal for all time to each individuals village, they perform missions, some assassinations and some excorts of important people or even just traveling merchants who cant seem to pass a certain point due to bandits or such, they perform ninjutsu allowing them to combat opponents on much larger scale, they also hone thier bodies by practising taijutsu or kenjutsu and in some cases even both.
2; Chakra is what is made when a shinobi connects his physical and spiritual energies together, kneeding this they create powerfull physcal manifestations that they use to combat one another, it can also transformed into different natures.
3; The five basic elements are nature transformations that can be applied to raw ninjutsu which allows the user to have even more arsenal of attacks against an opponent. These can range from breathing a fireball from your mouth or controlling the earth below, though each ninja has specialty meaning even if they can perform all elements, they only hold true mastery over one, except for thise who hold a kg or kt.
4; Ninjutsu is well, the connection between a shinobis physcal and spiritual energies creating chakra, which is then further used to manifest feats in the real world that wouldnt normally be possible, a great example is the rasengan, a ninjutsu that is pure chakra, nothing but that and it creates powerful blow when applied to physcal objects.
5; Well who wouldn't, its a usefull skill to hold in combat, if your by yourself you can use ninjutsu to create a clone to back you up, it hold many uses beyond that, like setting explosive tags under the ground, and controling them to explode via chakra which would warranted as a ninjutsu and i find thst pretty useful.