Question

A hard woody straight and pointed structure present on the axil of a leaf sometimes bearing leaves is called as
A. Bristle
B. Thorn
C. Prickle
D. None of these

Answer 1

There is a difference between the pointy structures on animals and plants and also, they have different names. Also look for the adaptation of various parts of the plants against their predators. Most of them are the modifications of leaves.

Complete answer:
A bristle is a stiff structure which can be present on the hairs of any animal and sometimes the spikes of porcupines are also known as bristles. This term can also be used for the hairs present on the brushes and other items.
There are three kinds of adaptations which plants can achieve in order to save themselves from the attack of predators. One of them is that the plants transform their leaves in the form of pointy structures and these structures are known as spines. This transformation is generally adapted by the plants to reduce the loss of water through the process of transpiration and can be generally seen in the plants of desert habitat.
The other adaptation of plants is the prickle, prickles arise from the extension of the hairs of the stem in the shoot or sometimes the epidermis of the stem into pointed structures. The prickles help the plant in a way that they will not get destroyed by the animals and can be used in the houses as a preventive measure for burglary.
The other adaption which is seen in the plants in of the stems of the plants which usually develops into the thorns but a major point of discussion in thorns is that they often bear leaves on them as they are the adaptation of the stems into pointy structure but the functionality and the anatomy will remain almost same. This is for preventing the rodents eating the plant leaves. The three different types of adaptation are seen in the leaves, stem, and axis of the plants.

So, the correct answer is option B.

Additional Information: The thorns and the spines are generally similar structures and they are known to have almost similar anatomy because of the presence of the vascular bundles inside them to form the required functions.

Note: Bristles cannot be compared with the thorns and prickles because the pointy nature of the bristles is due to its stiffness and the others are actually developed in order to be hard enough and tough.