The correct answer is "1 and 2 only" as the Kharai camel is indeed unique for its ability to swim up to three kilometers in seawater and its diet that primarily consists of grazing on mangroves, which enables it to thrive in coastal habitats. However, unlike the assertion in option 3, Kharai camels are not entirely wild and can be domesticated; they are managed and herded by local communities. Understanding the Kharai camel's adaptations highlights the intricate interplay between species and their environments, a concept critical in studies of biodiversity and ecology, particularly relevant in the context of climate change and habitat preservation as emphasized in UPSC syllabus.