Npk fertilizer is called a complete fertilizer, why?

Complete fertilizers or balanced fertilizers are so-called because of their amounts of nitrogen, phosphorus, and potassium. ... If your soil already had an excess of one of the three nutrients in NPK, you could actually be harming some of your plants by adding more of it to the soil

Explanation:

myth. it was once thought that animals, including cats and dogs, could only see in black and white. however, scientists have proven this to be a myth. in all animals, including humans, the perception of colour is determined by the presence of cells in the eye called cone photoreceptors.