Question

read the passage
the dead sea
found in southwestern asia, the dead sea isnt a sea at all. it is a salty lake, and it is much saltier than the ocean. in fact, the dead sea is so salty that no animals or plants can live in it. when fish are carried from the jordan river into the dead sea, they die right away. the water is even too salty for plants. in fact, there are only a few plants that can grow in the salty dirt near the lake. the dead sea certainly does live up to its name!
what is the main, or central, idea of the passage?
the dead sea is actually a very salty lake.
the dead sea is too salty to support plant or animal life.
any fish that enter the dead sea are killed right away.

Explanation:

The passage starts by stating the Dead Sea is a salty lake. Then it elaborates on its high salt - content consequences: no animals/plants in the water (fish die immediately when entering), only a few plants in the nearby dirt. The first option is too general as it just says it's a salty lake without highlighting the key aspect of unsuitability for life. The third option is too narrow (only about fish). The second option encompasses the main idea that the high saltiness makes it unable to support plant or animal life.

Answer:

The Dead Sea is too salty to support plant or animal life.