A flower can be regarded as perfect flower when:-
(a) Only one essential whorl is present
(b) Both essential whorls are present
(c) Both accessory whorls are present
(d) Both essential whorls are absent

Options

A. Only one essential whorl is present
B. Both essential whorls are present
C. Both accessory whorls are present
D. Both essential whorls are absent

Answer

To determine when a flower can be regarded as a perfect flower, we need to understand the definitions of essential and accessory whorls.

### Step-by-Step Solution:

1. **Understanding Flower Structure**:
- A flower consists of different whorls, which include essential whorls (androecium and gynoecium) and accessory whorls (calyx and corolla).

2. **Defining Essential Whorls**:
- The essential whorls are the reproductive structures of the flower. The androecium (male part) consists of stamens, and the gynoecium (female part) consists of carpels.

3. **Identifying a Perfect Flower**:
- A flower is considered perfect if it contains both essential whorls: the androecium and the gynoecium. This means that both male and female reproductive structures must be present.

4. **Evaluating the Options**:
- (a) Only one essential whorl is present: This indicates the flower is imperfect. **Incorrect**.
- (b) Both essential whorls are present: This is the definition of a perfect flower. **Correct**.
- (c) Both accessory whorls are present: Accessory whorls do not determine if a flower is perfect. **Incorrect**.
- (d) Both essential whorls are absent: This means there are no reproductive structures, so it cannot be a perfect flower. **Incorrect**.

5. **Conclusion**:
- The correct answer is (b) Both essential whorls are present.