Which of the following nutrients is vital for plant growth and development?

Nitrogen is a vital nutrient for plant growth and development because it plays a crucial role in several key physiological processes. As an essential macronutrient, nitrogen is a primary component of amino acids, which are the building blocks of proteins. Proteins are critical for the structure and function of plant cells, enabling processes such as growth, repair, and reproduction.

Moreover, nitrogen is an integral part of chlorophyll, the molecule that allows plants to photosynthesize. This process is fundamental, as it enables plants to convert sunlight into energy, fostering overall growth and vitality. Nitrogen also influences the development of foliage, promoting lush green leaves that are essential for effective photosynthesis.

In contrast, while other nutrients like silicon, sodium, and zinc have their own roles in plant health, they do not match the essential nature of nitrogen for growth, development, and overall plant productivity. Silicon can strengthen plant cell walls and may help with stress tolerance, sodium can be important in small amounts for some species, and zinc is crucial for enzyme function, but none of these nutrients fulfill the same foundational role that nitrogen does in terms of building proteins and supporting photosynthesis.