A
The element must be absolutely necessary for supporting normal growth and reproduction
B
The deficiency of any one element can be met by supplying some other element
C
The element must be indirectly involved in the metabolism of plants
D
The element must be absolutely necessary for supporting normal growth , but not necessary for reproduction
Solution:
According to Arnon the criteria for essentiality of an element are 1 - the element must be absolutely necessary for supporting the normal growth and reproduction. 2 - the requirement of the element must be specific and not replaceable by any other element 3- the element must be directly involved in the metabolism of the plant
