4
lesson pretestMultiple Choice

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Question 4 • TPS EdX Biology

Cacti typically grow in very dry climates with infrequent rainfall. When it does rain, the rain usually only penetrates a few inches into the soil. Which adaptation is most likely to help a cactus survive in the dry climate?

Answer
A
leaves that have a thin cuticle
B
extensive shallow roots that absorb water
C
more dermal tissue for food storage
D
thick xylem tissue to transport sugar

Explanation

Rain usually moistens only the top few inches of soil, so extensive shallow roots can quickly absorb water over a wide area before it evaporates. This adaptation helps the cactus make use of brief, infrequent rainfall. Xylem transports water and minerals, not sugar, and a thin cuticle would increase water loss.

AI-written and checked against the verified answer.

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