Question

One of the most resistant biological material is
a. Lignin
b. Hemicellulose
c. Lignocellulose
d. Sporopollenin

Answer 1

The most resistant biological material is extremely resistant to enzymes and other chemicals. It is chemically stable and remains unchanged for many millions of years and thus helps in preserving plant fossils.

Complete answer:
- Pollen grains are the microscopic powdery substances that contain male reproductive cell of the plant. It is the first cell of male gametophyte which is unicellular and haploid in nature.
- Pollen wall called sporoderm consists of two layers- the outer layer called exine and the inner layer called intine.
- The inner layer called intine is thin and uniform and made up of pecto-cellulose. The exine is thick and ornamented. At some places exine is absent or thin called germ pore. The exine is made up of a lipid nature substance called sporopollenin.
- Sporopollenin is biologically the most resistant organic substance. It makes pollen grain the most commonly preserved plant fossil.
- The pollen grains of different plant species vary in shape, size and other surface characteristics.

The study of pollen grains helps in various studies like:
- It can be used for archaeological studies and the reconstruction of past vegetation and several communities like marine and freshwater plankton.
- It can also be used in forensics to study a crime scene.
- Pollen grains also cause allergy and thus are also used for allergy studies.

Hence, the correct answer is option (D).

Note: Lignin, hemicellulose and lignocellulose are the parts of the cell wall of plant material. For example, collenchyma is made up of cellulose, hemicellulose and pectin material and the cells of sclerenchyma are also lignified. These materials provide strength to the cell wall of plants.