Which element forms part of the structure of the chlorophyll molecule?

In calcium-deficient plants,meristematic regions of the stem and root tips are greatly affected,and chlorosis of the margins of young leaves takes place. These symptoms eventually lead to the death of leaf,stem,and root apices. These observations are related to the role of calcium in plant growth as it is:

Which of the following is $NOT$ a micronutrient for plants?

Which of the following statements is incorrect?

How is sulphur important for plants? Name the amino acids in which it is present.

Which of the following is/are not an essential micro-nutrient?