T he fl atworm Schmidtea mediter-ranea (a freshwater planarian) can regenerate its entire body— including complex structures such as reproductive organs and its head—from a fragment as small as 1/279 th of the animal. What grants planarians this extraordinary regenerative capacity, and why don't humans share this power? It takes a person as resilient as a pla-narian to answer these kinds of que...

nowadays, population growth and on the other hand resources limitations astonish authorities. population changes cause variation in economic activities and land use changes. as a whole, overusing, improper land use and human disturbances over natural resources make environmental imbalances worse. in recent decades, we have seen land use changes in taleghan basin. land use changes were produced ...