Which one of the following is a wrong statement?

Given below are two statements:
Statement $I$: Diazotrophs are the nitrogen-fixing microorganisms,which are exclusively symbiotic.
Statement $II$: Organic fertilizers include farmyard manure,compost,and green manure.
In light of the above statements,choose the most appropriate answer from the options given below.

Analogy type questions:
$(1)$ Nitrogenase : Oxygen sensitive :: Leghaemoglobin : ........
$(2)$ Microbe on roots of Alnus : Frankia :: Roots of leguminous plants : Rhizobium :: Denitrification : Pseudomonas :: Biological nitrogen fixation : ........

Which mineral is present in milk?

Select the correct match for $X$ and $Y$:

Column $X$	Column $Y$
$(1)$ Mycorrhiza	$(P)$ Free-living $N_2$-fixer
$(2)$ Nostoc	$(Q)$ Phosphorus absorption
$(3)$ Azospirillum	$(R)$ Leguminous plants
$(4)$ Rhizobium	$(S)$ Autotrophic $N_2$-fixer

Which of the following statements are true? If false,correct them:
$(a)$ Boron deficiency leads to stout axis.
$(b)$ Every mineral element that is present in a cell is needed by the cell.
$(c)$ Nitrogen as a nutrient element,is highly immobile in the plants.
$(d)$ It is very easy to establish the essentiality of micronutrients because they are required only in trace quantities.