Government & Defence Entrance Exam

Definitely, you can. The previous performance isn't considered to judge you but you need to work hard to get a better result even if it is CMA, ACCA, CA, CS, or anything, you can do it.

Hi dear,
I will suggest you to go for army after completing your graduation. I appreciate your feelings towards the nation but if you want a good post and a nice position, you must first complete graduation. You may get details maybe on the below link:
http://www.apnaahangout.com/join-indian-army-officer-12th-science/
Good luck.

Dear Raju,
Government of India and state governments put maximum efforts to promote tourism in India. You can apply for it whenever notifications arrive.
All the best.

Now a day's, CCC is necessary for many government jobs in which basic computer knowledge is needed. So, it is good if you have this basic degree because it will make you eligible and add some opportunity in your career for applying government jobs. And you are an EC students, so I also think a little effort is needed to clear this exam because only CCC is needed in jobs.

To become an IPS officer, your graduation percentage will not matter. They just want you to be a graduate. But, they will definitely consider your rank in IAS exam.