Select the activites associated with gibberellins
(a) Apical dominance
(b) Good herbicides
(c) Promote bolting
(d) Delay senescence
(e) Stimulate closure of stomata.

Options

A. a and b only
B. b and c only
C. b and d only
D. c and d only.

Answer

To answer the question regarding the activities associated with gibberellins, we will analyze each option provided:

1. **Apical dominance (a)**: Apical dominance refers to the phenomenon where the main central stem of the plant grows more strongly than the side stems. This is primarily regulated by auxins, not gibberellins. Therefore, this option is **not associated with gibberellins**.

2. **Good herbicides (b)**: Gibberellins are not known to be effective herbicides. They are plant growth regulators and do not function as herbicides. Hence, this option is also **not associated with gibberellins**.

3. **Promote bolting (c)**: Bolting is the process where a plant rapidly grows and flowers, often in response to environmental conditions such as long days or cold treatment. Gibberellins play a significant role in promoting bolting in certain plants. Therefore, this option is **associated with gibberellins**.

4. **Delay senescence (d)**: Senescence is the process of aging in plants, leading to the death of leaves and fruits. Gibberellins have been shown to delay senescence, promoting longer life for leaves and fruits. Thus, this option is **associated with gibberellins**.

5. **Stimulate closure of stomata (e)**: The closure of stomata is primarily regulated by abscisic acid (ABA), especially in response to water stress. Gibberellins do not stimulate the closure of stomata. Therefore, this option is **not associated with gibberellins**.

### Conclusion:
The activities associated with gibberellins are:
- (c) Promote bolting
- (d) Delay senescence