Why is it important for soil to contain nitrogen, phosphorus, magnesium, and potassium??

Explanation:

1.Without enough nitrogen  in the soil the plant cannot grow taller, or produce enough food.

2.phosphorus results in higher grain production, improved crop quality, greater stalk strength, increased root growth, and earlier crop maturity. That is important because crops take up phosphorus only from the soil solution.

3.The role of Magnesium in the soil is the central core of the chlorophyll molecule in plant tissue. Thus, if Mg is deficient, the shortage of chlorophyll results in poor and stunted plant growth. Magnesium also helps to activate specific enzyme systems.

4. Potassium is a critical nutrient that plants absorb from the soil, and from fertilizer. It increases disease resistance, helps stalks to grow upright and sturdy, improves drought tolerance and helps plants get through the winter. Potassium triggers activation of enzymes and is essential for production of  (ATP).Both uptake of water through plant roots and its loss through the stomata are affected by potassium.

Hope this helped!!!

since there are no options posted i'll give you a few examples.

a dolphin's flipper, bird's wing, cat's leg.