1.Следует ли нам защищать живую природу?
Of course we should because we are part of nature. If wildlife perishes,we will perish too.
2. Следует ли нам защищать дельфинов?
Yes,we should. Dolphins are unique creatures. They are not big fish they are mammals that have consciousness. Also, dolphins save turtles when they sail for egg laying.
3.We must maintain the red fish because each type of fish is valuable and should be kept.
4.Следует ли нам защищать морских животных?
Quite so!Many sea animals keep the ocean clean. Also, after destroying one species of sea animals we can destroy some food chain, which will kill not only the themselves but also humans.
5.См.в 1-ом
6.см 2,3,4.