Photosynthesis produces carbohydrates, but plants contain many other types of biological molecule; such as proteins, lipids and nucleic acid (DNA)
As plants do not eat, they need to make these substances themselves
Carbohydrates contain the elements carbon, hydrogen and oxygen but proteins, for example, contain nitrogen as well (and certain amino acids contain other elements too)
Other chemicals in plants contain different elements as well, for example chlorophyll contains magnesium and nitrogen
This means that without a source of these elements, plants cannot photosynthesise or grow properly
Plants obtain these elements in the form of mineral ions actively absorbed from the soil by root hair cells
‘Mineral’ is a term used to describe any naturally occurring inorganic substance