The correct answer is option 'C' - Plasticity.

Explanation:
Plasticity refers to the ability of plants to alter their growth and development in response to changes in the environment or different phases of their life cycle. It allows plants to adapt and survive in diverse conditions.

Key Points:
1. Definition of plasticity: Plasticity in plants refers to their ability to modify their growth, development, and morphology in response to environmental cues or changes in their life cycle.
2. Environmental factors: Plants respond to various environmental factors such as light, temperature, water availability, nutrient availability, and gravity.
3. Examples of plasticity: Plasticity can be observed in various aspects of plant growth and development, including root architecture, leaf shape, stem elongation, and flowering time.
4. Root plasticity: Plants can adjust their root architecture in response to soil conditions. For example, in nutrient-poor soils, plants may develop longer and more branched roots to enhance nutrient uptake.
5. Leaf plasticity: Leaf shape can also be modified by plants in response to light availability. Plants grown in low light conditions may develop larger, thinner leaves to maximize light capture.
6. Stem plasticity: Plants can exhibit stem elongation in response to competition for light. When plants are shaded by neighboring vegetation, they may grow taller and elongate their stems to reach sunlight.
7. Flowering time plasticity: Plants can adjust their flowering time based on environmental cues such as photoperiod (day length) and temperature. This allows them to synchronize their reproductive phase with favorable conditions.
8. Benefits of plasticity: Plasticity provides plants with the ability to optimize their growth and development in different environments, increasing their chances of survival and reproduction.
9. Plasticity and evolution: Plasticity plays a crucial role in plant evolution by allowing plants to adapt to changing environmental conditions. It contributes to the diversification and specialization of plant species.
10. Significance in agriculture: Understanding the plasticity of crop plants can help in developing strategies to enhance their productivity and resilience to environmental stressors.

In conclusion, plasticity is a fundamental characteristic of plants that enables them to respond and adapt to changes in their environment or life cycle. It allows plants to alter their structures and behaviors, optimizing their growth and survival.