Question

Critical elements are
A. Na, K and Ca
B. N, P and Mg
C. N, P and K
D. Mn, B and Mo

Answer 1

Besides water and sunlight, plants need several nutrients to grow which is obtained from the soil. The essential nutrient elements are divided into macronutrients and micronutrients. Nutrients that are required in large amounts are called macronutrients and in low amounts are considered as micronutrients. Examples; carbon, hydrogen, oxygen, nitrogen, calcium, magnesium and sulfur.

Complete step by step answer: The concentrations of N, P, Mn, and Al in plants are different from species to species. According to the latest research data, plants invariably possess higher concentrations of N and P and lower concentrations of Al and Mn. In different plant species, the composition of essential elements in the evergreen species was not significantly different for any of the elements from that of the deciduous species. Broad evergreen leaves of plants appear to manufacture more photosynthate per acquired unit of N or P than deciduous leaves, primarily because of their longevity. The high occurrence of ever green-ness in infertile environments may, therefore, reflect a decreased need to acquire N and P from a substrate deficient in these elements.
Hence, the correct answer is option C.

Note: Justus von Liebig identified the chemical elements of nitrogen, phosphorus, and potassium is essential to plant growth in his theory of mineral nutrients. He reported that plants acquire carbon and hydrogen from the atmosphere and from water, and the remaining other nutrient elements are acquired from the soil and fertilizers.