Question

Which of the following are called primary elements?

• A. Ca, Na, Mg, Fe
• B. C, H, O, N, P
• C. Fe, Mo, Mn, B
• D. Ca, Mg, P, K

Answer 1

Answer: (B)

C, H, O, N, P

17 essential elements required by plants for normal growth, development and reproduction. These are either macronutrients, required in large amount or micronutrients, required in small amount. Macronutrients are of three types, primary, secondary and tertiary elements. Primary elements derived from air and water include carbon, hydrogen and oxygen. Other primary elements include phosphorous, potassium and nitrogen. Secondary and tertiary elements include sulfur, magnesium and calcium.

Thus, the correct answer is option B.