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Q17 (NDA-II/2016) Science & Technology › Basic Science (Physics, Chemistry, Biology) › Plant anatomy physiology Answer Verified

Consider the following statements about cactus: 1. The leaves are reduccd to spjncs. 2. The stem does the photosynthesis. Which of the statements given above is/are correct ?

Result
Your answer: —  Â·  Correct: C
Explanation

Cacti are xerophytic plants that have evolved specific adaptations to survive in arid desert conditions. Statement 1 is correct because cacti have leaves that are reduced to spines to minimize water loss through transpiration and to provide protection against herbivores [3]. Statement 2 is also correct because, in the absence of functional leaves, the stem becomes succulent and green, containing chlorophyll to perform photosynthesis [3]. This modified stem, often referred to as a phylloclade, also serves as a primary storage organ for water to sustain the plant during long droughts [1]. While leaves are the primary site for photosynthesis in most plants, other green parts like the stem can perform this function if they contain chlorophyll . Therefore, both statements accurately describe the physiological and morphological adaptations of a cactus.

Sources

  1. [1] Certificate Physical and Human Geography , GC Leong (Oxford University press 3rd ed.) > Chapter 18: The Hot Desert and Mid-Latitude Desert Climate > Natural Vegetation > p. 176
  2. [3] Science-Class VII . NCERT(Revised ed 2025) > Chapter 10: Life Processes in Plants > 10.2.2 Role of air in the preparation of food > p. 144
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