Given below are five statements (i-v) regarding constrivances to ensure cross - pollination is plants
(i) Dicliny - Anthers stigmas mature at different times in a bisexual flower.
(ii) Dichogamy - Flowers are unisexual.
(iii) Prepotency - Pollen grains of the same flower germinate more rapidly over the stigma than the pollen grains another flower.
(iv) Heterostyly - Two or three types of flowers with different heights of styles.
(v) Herkogamy - A mechanical device to prevent self - pollination
which of the above statement are correct ?

Options

A. (i) and (ii)
B. (i), (ii) and (iii)
C. (iii) , (iv) and (v)
D. (iv) and (v)

Answer

To determine which of the five statements regarding contrivances to ensure cross-pollination in plants are correct, let's analyze each statement step by step:

### Step 1: Analyze Statement (i)
**Statement (i): Dicliny - Anthers and stigmas mature at different times in a bisexual flower.**
- **Analysis**: This statement is incorrect. The correct term for when anthers and stigmas mature at different times in a bisexual flower is "Dichogamy," not Dicliny. Dicliny refers to the condition where flowers are unisexual (either male or female).

### Step 2: Analyze Statement (ii)
**Statement (ii): Dichogamy - Flowers are unisexual.**
- **Analysis**: This statement is also incorrect. Dichogamy refers to the maturation of anthers and stigmas at different times in bisexual flowers, allowing for cross-pollination. Unisexual flowers are a characteristic of Dicliny.

### Step 3: Analyze Statement (iii)
**Statement (iii): Prepotency - Pollen grains of the same flower germinate more rapidly over the stigma than the pollen grains of another flower.**
- **Analysis**: This statement is incorrect. Prepotency refers to the ability of one parent to transmit more characteristics to the offspring than the other parent, not the rate of germination of pollen grains.

### Step 4: Analyze Statement (iv)
**Statement (iv): Heterostyly - Two or three types of flowers with different heights of styles.**
- **Analysis**: This statement is correct. Heterostyly involves the presence of flowers with different lengths of styles and stamens, promoting cross-pollination by ensuring that pollen from one flower type is more likely to reach the stigma of another flower type.

### Step 5: Analyze Statement (v)
**Statement (v): Herkogamy - A mechanical device to prevent self-pollination.**
- **Analysis**: This statement is correct. Herkogamy refers to structural adaptations in flowers that prevent self-pollination, thus promoting cross-fertilization.

### Conclusion
From the analysis:
- **Correct Statements**: (iv) Heterostyly and (v) Herkogamy.
- **Incorrect Statements**: (i), (ii), and (iii).

### Final Answer
The correct statements regarding contrivances to ensure cross-pollination in plants are **(iv) Heterostyly** and **(v) Herkogamy**.

---