Which one of the following is not an essential
mineral element for plants while the remaining
three are ?
Which one of the following is not a micronutrient?
About 98 percent of the mass of every living organism is composed of just six elements including carbon, hydrogen, nitrogen, oxygen and:
1. phosphorus andf sulphur
2. sulphur and magnesium
3. magnesium and sodium
4. calcium and phosphorus
Which one of the following elements is not an essential micronutrient for plant growth?