Which of the following is the modification of leaf?

In sweet pea,the tendrils are modified:

Sheathing leaf base is found in $-$

In $Acacia$ species,the first few leaves are pinnately compound. Then there are leaves with flattened petiole and fewer pinnae. The leaves of the adult plant have parallel-veined flattened petioles and no pinnae. It shows that:

Presence of sheathing leaf base and ligule are characteristic of

Which tissue constitutes the pulvinus of a leaf?