Question

read the passage.
blooms in death valley
in march 2016, death valley national park in california experienced a rare occurrence: thousands of yellow wildflowers covered the region in a \super bloom.\ why was this unusual? death valley is the hottest and driest place in north america. the areas average yearly precipitation is just two inches, making it a challenging place for flowers to grow. however, in october 2015, the valley had received more than three inches of rain in some areas. as a result of the unusually wet season, wildflower seeds that had been lying dormant underground suddenly began to grow, producing an abundance of golden blooms.
what is the main, or central, idea of the passage?
because of an unusual amount of rain, thousands of wildflowers grew in death valley in 2016.
because of the hot, dry conditions in death valley, it is difficult for flowers to grow there.

Explanation:

The passage starts by presenting the rare occurrence of wildflowers in Death Valley in 2016. Then it explains that Death Valley is usually hot and dry (making it hard for flowers to grow). But due to an unusual amount of rain in 2015, the wildflower seeds grew. The first option encompasses both the event (wildflowers growing) and the cause (unusual rain), which is the main idea. The second option only focuses on the usual difficulty of flower - growth in Death Valley and doesn't mention the 2016 event which is the main focus of the passage.

Answer:

Because of an unusual amount of rain, thousands of wildflowers grew in Death Valley in 2016.