What words will correct fill (a) , (b),(c) and (d) in the following paragraph ?
(a) developed into a pollen grain. The outer layer is (b) and inner layer is intine . The inner layer is made up to cellulose and ( c) .In 60% of the angiosperms, pollen grains are shed at (d) celled stage .

Options

A. (a) - Anther , (b) - Exine , (c) - Chitin , (d) - 3
B. (a) - Microspore , (b) - Exine , (c) - Chitin (d) -2
C. (a) - Anther , (b) - Exine , (c) - Pectin , (d) - 2
D. (a) - Microspore , (b) - Exine , (c) - pectin, (d) -2

Answer

To fill in the blanks of the given paragraph, we need to identify the correct terms related to the structure and development of pollen grains in flowering plants. Here is the step-by-step solution:

1. **Blank (a)**: The term that develops into a pollen grain is "microspore". In the process of microsporogenesis, microspores are produced in the anthers of flowers, which later mature into pollen grains.

**Hint**: Think about the initial stage of pollen grain formation in flowering plants.

2. **Blank (b)**: The outer layer of the pollen grain is called "exine". This layer is known for its toughness and is made of a resistant substance called sporopollenin.

**Hint**: Consider the protective outer layer of pollen grains that is resistant to environmental factors.

3. **Blank (c)**: The inner layer of the pollen grain is made up of cellulose and "pectin". The entine, which is the inner layer, provides structural support and is composed of these substances.

**Hint**: Look for a polysaccharide that is commonly associated with plant cell walls and provides flexibility.

4. **Blank (d)**: In 60% of angiosperms, pollen grains are shed at the "two" celled stage. This means that when the pollen grains are released, they typically consist of two cells: one vegetative cell and one generative cell.

**Hint**: Think about the number of cells present in pollen grains at the time of their release in most flowering plants.

Putting it all together, the filled paragraph would read:

(a) microspore developed into a pollen grain. The outer layer is (b) exine and the inner layer is intine. The inner layer is made up of cellulose and (c) pectin. In 60% of the angiosperms, pollen grains are shed at (d) two celled stage.

**Final Answers**:
(a) microspore
(b) exine
(c) pectin
(d) two