In sweet pea tendrils are modified ___________.
Tendrils are a type of slender, spring-like structures which are coiled spirally. They are sensitive to contact. So, when they come in contact with any support, they easily coil around the support. Vines are having tendrils, which are formed from a leaf part of the plant. The pea family have such tendrils which are formed from the leaflet of the compound leaves. But, not all tendrils are as modified leaves, tendrils of cucumber are modified stem.
Thus, the correct answer is option D.