Select the incorrect statement from the following options.

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.

The soil organisms are

$A$ 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.

Match the columns:
$I$ $II$
$(A)$ Magnesium $(i)$ Found in middle lamella
$(B)$ Sulphur $(ii)$ $A$ structural component of chlorophyll
$(C)$ Calcium $(iii)$ Required for enzyme activity
$(D)$ Iodine $(iv)$ Found in some amino acids
$(E)$ Manganese $(v)$ $A$ component of sugars
$(vi)$ Not important for plants

Which of the following is a free-living nitrogen-fixing bacterium?