Creeping thistle continuously survives through easy germination of seeds. The Creeping thistle seed can be buried in undisturbed soil for over 20 years and still become growable. And also, the roots help in their growth. They absorb nutrients and regenerate to form new plants. Although the roots may be able to penetrate some meters down, most regeneration occurs within or just below the plow layer. Portions of the adjacent roots become thick due to the developing storage tissue which is where new shoots are formed.
One of the changes in development and specialization that did not happen in primitive mammals was the increase in stomach capacity. The specialization of teeth and the lower jaw are two important modifications of the primitive mammals. Also an increase in size and brain capacity are two crucial modifications of the early mammals.
Answer:
The crust is not the thickest layer of earth
:)
