What is the main idea of the passage?

The cactus has changed its shape in many ways to save water in the desert (Each feature of the cactus is shown to serve one goal: saving water.)

According to the text, what does the cactus have instead of wide, flat leaves?

Sharp spines (The text says "the cactus has traded its leaves for sharp spines.")

Why does the cactus have shallow roots that spread out wide?

To drink in rain quickly before it sinks away (The text says the roots are "ready to drink in any rain before it sinks away.")

In this passage, "thrives" most nearly means

grows well and strong (The cactus "not only survives... it thrives," so thrives means does well, more than just survive.)

How the Cactus Survives: Level 2 Reading Comprehension Questions

A desert can go months, even years, without rain. Under a burning sun, most plants would dry out and die. Yet the cactus not only survives there, it thrives. Over long ages, the cactus has changed its very shape to hold on to water.

Its thick, rounded stem works like a tank. When rain finally comes, the stem swells and fills, storing water for the dry months ahead. A waxy skin covers the plant and seals that water in, so little escapes into the hot air.

Most plants have wide, flat leaves, but wide leaves lose water fast. The cactus has traded its leaves for sharp spines. The spines lose almost no water, and they guard the juicy stem from thirsty animals.

Shallow roots spread out wide, just under the surface, ready to drink in any rain before it sinks away. Every part of the cactus is built for one task: to save water.

Comprehension questions