Phyllotaxy is the pattern of arrangement of $ . . . . . . $.

Assertion $(A)$: Reticulate venation is observed in the leaves of sunflower.
Reason $(R)$: Sunflower is included in the class Dicotyledonae.

In $........$,the stipules are modified into tendrils.

Which of the following statements is incorrect regarding a leaf?

How do the various leaf modifications help plants?

In $Opuntia$ (prickly pear),the spines are modified forms of: