Question

In sweet pea, the tendrils are modified
A. Stem branches
B. Leaflets
C. Leaves
D. Stipules

Answer 1

Tendrils are nothing but thin, thread-like structures or appendages which were climbing from the plants, and sometimes they may grow into spiral form at the end, that spiral forms may stretch out and it twines around immediately with suitable support.

Complete answer:
Tendrils may be formed from the modified roots or modified leaves, or from the auxiliary branches which are sensitive to the chemicals.
Charles Darwin was a scientist who has done an early study on the tendrils, and the study is called Darwin monograph, were from that studies, he wrote and published a book called Movements and Habits of the climbing plant which was published in the year 1865.
At the same time, in this study, he observed the motion of growing stems, and he coined the term circumnutation in order to describe the movement of growing stems and as well as the tendrils which are taking the support.
And he also observed the phenomenon called tendril perversion.
Whereas in the sweet pea, it is nothing but the terminal leaflet, which is modified to form the tendrils.
Whereas in some other plants like yellow vetch, the whole leaf is modified to form the tendril, and in this plant, photosynthesis is carried out by the stipules.
So in so many plants, various parts are modified into tendrils, which include the leaf, upper leaflets, terminal bud, and petiole or stipules.
So as from the above explanation, in the sweet pea, they are formed from the leaflets, so the answer is leaflets.

So, Correct option is B. leaflets.

Note: Some of the examples of plant parts that are modified to tendrils.
In the wild pea—it is an entire leaf.
In the sweet pea-- it is a terminal leaflet.
In the passiflora—it is formed from the terminal bud.
In the Gloriosa it is formed from-- leaf tip.
In the Clematis-- it is formed from the petiole.
Whereas in the Smilax-- it is formed from the Stipule.