What does this "it" refer to? "Its innovative approach" or "that" clause after? I don't think "prove" can be used as an intransitive verb here.
74)...Today, there are more than 1000 Grameen branches in Bangladesh, and they have made loans to more than 2 million people from 37,000 villages. Its innovative approach to the relationship between financial institutions and the working poor has made a big difference in the lives of millions of people. Moreover, it has proven that, given an opportunity and a little support, people can pull themselves out of poverty.