Ammonium sulphate is:

Phosphorus is required for making
$I.$ shell
$II.$ bones
$III.$ teeth
Choose the correct option

Which one of the following is a wrong statement?

$A$: Plants absorb nitrogen from the soil in the form of salts.
$R$: Nitrogen is essential for the synthesis of proteins and nucleic acids.

Which of the following statements are incorrect?
$I.$ Hemoglobin,myoglobin,and cytochromes are iron-containing compounds.
$II.$ Copper is important for cell division in plants.
$III.$ Biotin and riboflavin are sulfur-containing vitamins.
$IV.$ Calcium is necessary for the structure of teeth and bones.
$V.$ Manganese is required in the structure of the phosphatase enzyme.

$A$ farmer adds/supplies $Na, Ca, Mg$ and $Fe$ regularly to his field and yet he observes that the plants show deficiency of $Ca, Mg$ and $Fe$. Give a valid reason and suggest a way to help the farmer improve the growth of plants.