I want to become Marine Biologst. How to apply for Marine Biology after 10th standard? Which college to join ?Ordinary college or any special marine biology college?

The first two years of college are about the same for any major. You would start studying general biology first and move on to specialized courses and your last year you would probably be studying nothing but biology courses. I would pick a college close to the shore so you can do field work, and decide on whether that's to be on the Pacific coast or Atlantic coast or even Gulf of Mexico.