Give scientific reasons: $Opuntia$ has phylloclade.

(N/A) $\rightarrow$ $Opuntia$ is a xerophytic plant. Due to the dry atmosphere,less water is available from the soil. To prevent the loss of water,leaves are shed,become small,or are converted into spines. In the absence of leaves to perform photosynthesis,the stem becomes broad,flat,green,and contains chlorophyll,acting like a leaf. This modification of the stem into a leaf-like structure is called a phylloclade.