Consider the following statements regarding mangrove vegetation and choose the correct answer:
1. True mangrove vegetation occurs in open beach or in sandy or rocky shores of the sea
2. The vegetation rarely develops in wet tropics where the tropical rain forest is the climax vegetation
3. In world, the eastern mangrove is found on the coasts of Indian ocean and the western part of the Pacific ocean
4. Most of the species of mangrove formations are gregarious in habit