How are cactus adapted to survive in a desert?

Explanation

**Step-by-Step Text Solution:**

1. **Understanding the Environment**: Cacti are found in deserts, which are characterized by very low water availability. This environment poses a challenge for most plants, as they need water to survive.

2. **Modification of Leaves**: In cacti, the leaves are modified into spines. This adaptation serves a crucial purpose: it helps to prevent water loss. Normally, leaves have stomata (tiny openings) that allow for gas exchange but also lead to water loss through a process called transpiration. By having spines instead of broad leaves, cacti minimize this water loss.

3. **Modification of Stems**: The stems of cacti are adapted to store water. They are thick and fleshy, allowing them to hold large amounts of water during rare rainfall. Additionally, the stems are also responsible for photosynthesis, the process through which plants make their food. In cacti, the stems perform this function instead of the leaves.

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