Read the passage given below and answer the following question.

The pollen grains, serve as the male gametophytes in flowering plants. Upon touching the opened anthers of flowers like Hibiscus, one can observe the deposition of yellowish powdery pollen grains on their fingers. When these grains are sprinkled on a glass slide with a drop of water and observed under a microscope, a fascinating variety of architecture, including sizes, shapes, colors, and designs, can be seen among the pollen grains from different species.Pollen grains are generally spherical and have a diameter ranging from 25 to 50 micrometers. They possess a two-layered wall, with the outer layer composed of sporopollenin, which exhibits intricate patterns and designs. The inner wall of the pollen grain is a thin and continuous layer. When mature, the pollen grain contains two cells: the larger vegetative cell and the smaller generative cell. The vegetative cell holds abundant food reserves and a large, irregularly shaped nucleus, while the generative cell floats within the cytoplasm of the vegetative cell.In the majority of angiosperms (over 60 percent), pollen grains are shed at the 2-celled stage, where they contain vegetative and generative cells. However, in the remaining species, the generative cell undergoes mitotic division to produce the two male gametes before the pollen grains are shed, resulting in a 3-celled stage.

What is the outer layer of pollen grains known as?( Question 4)

Exine

The correct answer is Option (2)- Exine

The outer layer of pollen grains is known as the exine. The exine is the tough and durable layer that surrounds the inner contents of the pollen grain, providing protection and structural support.

It is primarily composed of a complex biopolymer called sporopollenin, which gives the exine its characteristic resilience and resistance to degradation.

The exine often exhibits intricate patterns, designs, and ornamentation that are unique to each plant species and can be observed under a microscope.