Which substance is essential for cellular processes and often limited by environmental conditions during plant growth?

The substance that is essential for cellular processes in plants and can often be limited by environmental conditions is water. Water plays a crucial role in various physiological functions, including photosynthesis, nutrient transport, and maintaining turgor pressure within cells, which is vital for plant structure and growth.

In many environments, especially during periods of drought or in arid regions, the availability of water can severely restrict plant growth and development. When water is limited, plants may experience stress, leading to wilting, reduced photosynthesis, and ultimately lower yields.

While light, nutrients, and soil are also important for plant growth, their availability does not fluctuate as dramatically in some conditions as water does. Light can be abundant in certain situations, nutrients can be supplemented through fertilization, and while the quality of soil can vary, it does not change abruptly like water availability can due to weather patterns. Thus, water’s critical role in cellular processes and its susceptibility to environmental conditions make it the correct choice.