Cobalt is one of the elements which is classified as an essential element, although it does classify as a micronutrient because of the fact that it is not required in as high of a concentration as opposed to a macronutrient like phosphorous.

Chlorine plays a very important part in photosynthesis, particularly in helping to control the hydrolysis process. It also aids in the process of cation balance as well as the transport of ions and nutrients throughout the plant system.