Question

How do the sharp spines on the cactus help it to survive?

Answer 1

In cactus, leaves shrink down to form spines/thorns. This helps it in 2 ways -
1) Protects it from herbivores
2) Prevents water loss which occurs via transpiration in leaves.

Answer 2

HEY mate !! HERE is your answer !!
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Mainly cactus plants grow in desert areas and also hot regions where the rainfall amount is very less and there is a deficit of water so in this condition cactus modifies its leaves into spine which retards the rate of transpiration (the process in which the plants leave excess water in the form of water vapour) which helps it to survive in insufficient water.
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Hope it helps you.

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