Final answer:
The key factor in moisture that determines a plant's need is humidity, as it influences water uptake and transpiration rates. Humidity, along with soil type, importantly influences plant growth and can affect the net primary productivity in different ecosystems.
Step-by-step explanation:
The key factor in moisture that determines a plant's need is humidity. Humidity affects transpiration rates in plants and can influence water uptake. If the humidity is high, there is a reduced evaporation rate because there is a smaller difference in water vapor pressure between the leaf and the atmosphere.
Soil quality and climate are significant determinants of plant distribution and growth, impacting the availability of water and nutrients required for photosynthesis along with other vital processes. Therefore, a proper balance of moisture and soil type is crucial for optimal plant health and productivity.
Humidity factors into the availability and retention of water in the soil, which is the main water source for land plants. This relationship is vital for understanding how abiotic factors like temperature and moisture influence plant growth in different biomes, and the net primary productivity of those ecosystems.