What is nutrient immobilisation?

Analogy type questions:
$(1)$ Manganese toxicity : Brown spots surrounded by chlorotic veins : Molybdenum deficiency : ........
$(2)$ Conversion of nitrogen to ammonia : Nitrogen fixation : Oxidation of nitrite to nitrate : ........

Match the following columns:

Column-$I$	Column-$II$
$1.$ Mycorrhiza	$a.$ Free-living $N_2$-fixer
$2.$ Nostoc	$b.$ Phosphorus absorption
$3.$ Azospirillum	$c.$ Leguminous plants
$4.$ Rhizobium	$d.$ Autotrophic $N_2$-fixer

Which mineral is present in milk?

Which of the following plants is used as green manure in crop fields and in sandy soils?

Select the correct option:
$(1)$ During $transamination$ / $reductive$ $amination$,an amino group is transferred from one amino acid to the keto group of a keto acid.
$(2)$ $Azotobacter$ / $Clostridium$ are free-living bacteria.