题目内容：

    Plants on mountains

Mountains are more than 500 meters tall and it’s not easy for plants to live on them. The wind is strong. The soil is thin and rocky. Which plants can live there? Come and see some of them.

	They look like a small cushion(垫子). They grow together and they are less than 30 cm tall. But they can be 3 meters wide. People also call the plants “ecosystem engineers”. That’s because many other plants live under them. Cushion plants keep the cold away. They make the soil inside soft and wet. In this way, cushion plants help other plants survive(生存).
	The snow lotus lives at elevations ranging from 2,400 to 4,000 meters. The climate there is cold. It always snows and the air is thin. Most plants will die. But the snow lotus grows well. A snow lotus can be 15 to 35 cm tall. People use it in medicine.
	The evergreen saxifrage has star-shaped flowers. Most saxifrages are very small — less than 12 cm tall. They grow very slowly in cold environments. Saxifrages can live both in the mountains and in your garden, yet they are not resistant (耐受的) to high temperatures.

 

 

1.According to the passage, which are the smallest plants?

A.Cushion plants B.Snow lotuses C.Saxifrages

2.What do we know about cushion plants?

A.They can grow up to 3 meters tall.

B.They can protect the plants under them from the cold.

C.They need to live in soft and wet soil.

3.Which plants can be used in medicine?

A.Cushion plants B.Snow lotuses C.Saxifrages