i m in big confusion that why my interviews got rejected or applications got rejected
Is this for jobs? Firstly, if you use grammar as you have done on this thread then that will definitely be a reason your applications are rejected. When you have 100 applications to sift through getting rid of those that don't capitalise an 'I' is a quick win.
As for your interview. You are there to show that you have the skills and knowledge required to do the job they want you to do. So you need for frame your answers in a style which reassures them you have what it takes to help make them money.