Plant Growth And Development

To solve this question, we need to identify the plant hormone responsible for phototropism.

1. Understanding Phototropism:
Phototropism is the growth of a plant in response to light. It occurs when the plant's stem grows towards light sources. The hormone responsible for this directional growth is auxin.

2. Role of Auxin in Phototropism:
Auxin accumulates on the shaded side of the plant stem, causing the cells on that side to elongate. This differential growth causes the plant to bend towards the light source.

3. Evaluating the Options:

• (A) Cytokinin – Incorrect; cytokinin is involved in cell division, not phototropism.
• (B) Gibberellin – Incorrect; gibberellin is involved in growth processes like stem elongation but not specifically phototropism.
• (C) Auxin – Correct; auxin is the hormone responsible for phototropism. ✔
• (D) Abscisic acid – Incorrect; abscisic acid regulates processes like seed dormancy and stress response, not phototropism.

Final Answer:
The correct answer is (C) Auxin.

To solve the problem, we need to identify the method of plant propagation in which two stems are joined to grow as one plant.

1. Understanding Grafting:
Grafting is a horticultural technique where tissues of plants are joined so that they continue their growth together. It is commonly used to propagate fruit trees and ornamental plants.
- The scion (a stem from the desired plant) is joined to the stock (the rooted plant).
- Over time, they fuse and grow as one single plant.

2. Elimination of Other Options:
- Layering: Involves bending a stem to the ground to encourage roots to form while still attached to the parent plant.
- Cutting: A method where a piece of plant is cut and planted to grow independently.
- Conjugation: A type of sexual reproduction in microorganisms, not related to plants.

Final Answer:
The process of joining two stems to grow as a single plant is