题目

The Golden Gate Bridge in San Francisco，California is one of the world's most beautiful bridges. It is also one of the most visited places in the world. Vehicles cross the bridge an average of 41 million times each year. More than 1800 hundred million vehicles have used the bridge since it opened more than 70 years ago.       The bridge was painted “International Orange” because that color went well with the natural surroundings. The color also is easier to see in the heavy fog that often covers the area. But the Golden GateBridge was not named for its orange color. It was named 种子萌发过程中，最先发生的变化是（ ）A．种子内的营养物质转化成胚可以吸收的成分B．胚根突破种皮C．胚轴伸长D．胚芽发育成茎和叶