Analogous type questions:
$(1)$ Macronutrient : Nitrogen :: Micronutrient : ....
$(2)$ Carboxylase : Zinc :: Nitrogenase : .......

$P$: Phosphorus is essential for normal growth and reproduction in our body.
$Q$: Copper is important in the synthesis of chlorophyll in plants.

In green plants,boron is required for:

Choose the incorrect pair.

Which mineral is essential for the repair of worn-out cells in our body?

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: