(I) The formation of microspore from microspore mother cells by meiosis is called ........a .......
(II) Formation of megaspore from megaspore mother cell by meiosis is called .......b...........
(III ) The formation of male gamete from generative cell by mitosis is called ...........c.......
(IV ) The formation of a zygote by the fusion of male and female gametes is called ......... d.........
Write correct terms for a, b, c and d.

Options

A. `{:(A,B,C,D),("Megasporagenesis","Microsporogenesis","Fertilization","Gametogenesis"):}`
B. `{:(A,B,C,D),("Microsporogenesis","Megasporagenesis","Microgametogenesis","Fertilization"):}`
C. `{:(A,B,C,D),("Microgametogenesis","Megasporagenesis","Microsporogenesis","Syngamy"):}`
D. `{:(A,B,C,D),("Syngamy","Microgametogenesis","Microsporogenesis","Microgametogenesis"):}`

Answer

To answer the question, we need to fill in the blanks with the correct biological terms related to the processes of gamete formation and fusion. Let's break it down step by step:

### Step-by-Step Solution:

1. **(I)** The formation of microspore from microspore mother cells by meiosis is called **Microsporogenesis**.
- **Explanation**: Microsporogenesis is the process where microspore mother cells undergo meiosis to produce microspores, which eventually develop into pollen grains.

2. **(II)** Formation of megaspore from megaspore mother cell by meiosis is called **Megasporogenesis**.
- **Explanation**: Megasporogenesis refers to the process of meiotic division in megaspore mother cells, resulting in the formation of megaspores, which develop into the female gametophyte.

3. **(III)** The formation of male gamete from generative cell by mitosis is called **Gametogenesis** (or specifically **Microgametogenesis**).
- **Explanation**: Gametogenesis is the process of forming gametes. In this context, it refers to the formation of male gametes from the generative cell through mitotic division.

4. **(IV)** The formation of a zygote by the fusion of male and female gametes is called **Syngamy**.
- **Explanation**: Syngamy is the process of fusion of male and female gametes, resulting in the formation of a diploid zygote.

### Final Answers:
- a: Microsporogenesis
- b: Megasporogenesis
- c: Gametogenesis (or Microgametogenesis)
- d: Syngamy