Thousands of years ago, in the middle of an ocean, miles from the nearest island, an under

sea volcano broke out. The hot liquid piled higher and higher and spread wider and wider. In this way, an island rose up in the sea.

(15) As time went on, hot sun and cool rains made the rock split and break into pieces, sea waves dashed against the rock. In this way, soil and sand came into being.

Nothing lived on the naked soil. And then the wind and birds brought plant seeds, spiders and other little creatures there. Only plants could grow first. Only in sunlight could they produce food from the minerals of the soil, water and air. While many animals landed on the island, they could find no food. A spider spun its web in vain, because there were no insects for its web to catch. Insects couldn't stay until there were plants for them to eat. So plants had to be the pioneer life on this new island.

The passage centers on______.

A．how an undersea volcano broke out

B．how an island rose up in the sea

C．how soil was formed on a new island

D．how life began on a volcano-produced island