Question

How twiners and tendrils make a round around the support

Answer 1

When the tendrils come in contact with another surface or object, the area in contact becomes sluggish.... this leads to the growth in rest of the part and slower growth of the part in contact... Hence the tendril forms a loop arond the object or surface. Tis is an example of thigmotropism

Answer 2

they make round because of plant growth hormone