Entry of mineral ions in plant root cells by diffusion is

By which method are ions absorbed by plants?

Minerals are known to enter the plant root by means of a number of mechanisms,including all except one of the following. Which one of the following is $NOT$ a mechanism for moving minerals into roots?

Boron is absorbed by plants in the form of:

Cabbage plants absorb phosphorus from which of the following?

Iron is absorbed from the soil in the form of .......