Question

Cacti are well-known for their ability to store water, allowing them to thrive in arid environments. Like all species of cacti, the saguaro cactus stores water in its thick stem, which can expand dramatically during periods of heavy rainfall. In this way, the saguaro can survive years of drought.

And while no one would call the saguaro cactus small—it can grow as tall as 12 meters—it is not the largest cactus species. That title goes to the Mexican giant cardon cactus, which can grow up to 20 meters tall and store significantly more water due to its larger size.


4

Which choice best describes the overall structure of the text?

A
It describes a characteristic shared by all cacti and then illustrates a difference between the saguaro cactus and the Mexican giant cardon cactus that is relevant to that characteristic.

B
It discusses a unique feature of the saguaro cactus and how the lack of that feature in the Mexican giant cardon cactus explains differences in the two species’ water storage.

C
It draws a distinction between the sizes of the saguaro cactus and the Mexican giant cardon cactus and then presents a feature that they have in common.

D
It details a relationship between the saguaro and Mexican giant cardon cacti and water storage and then discusses an unexpected consequence of a change in cactus populations.

Answer 1

A

The passage first states a general water-storage trait of cacti (using the saguaro as an example) and then contrasts the saguaro with the larger Mexican giant cardon, noting the cardon’s greater water storage.