Plants with a primary root and little lateral roots that extend out from it have a system.

Plants with a primary root and little lateral roots that extend out from it have a tap root system.

A taproot system, generally found in dicotyledons, is made up a central, large pointed root and this is what is called the taproot.

Smaller roots branch off from the taproot and are known as lateral roots. The tap root is larger in diameter than the lateral roots. Tap roots generally grow much more deeply into the soil compared to fibrous roots.

i believe it is "they are not used up by reactions" as the answer to your question, text me back if this is correct because i just learned this.

substitution is the answer in this case