55. Which of the following is right?

A. The journey lasted 100 days.

B. Each boat was different.

C. It was hard to get to the end of the race.

D. Debra Veal wanted to leave her boat as soon as the race ended.

(B)

We all cry for water when we are thirsty. But do you know,  in very hot,  dry weather,  plants also make very low sounds ― as if they are crying out for help?

You see,  in a plant's stem(茎) there are several hundred "water pipes(管道)" that bring water from soil all the way up to the leaves. When the ground turns dry,  it becomes harder and harder for plants to do this.

In very hot days,  plants have to get any water that it can.

Scientist Robert Winter has found out that when plants can get no water, their "water pipes" snap(发出断裂声) . When that happens,  the whole plant vibrates( 振动 ) a little. The snapping pipes make noises ten thousand times more quiet than a whisper(低语).