Answer to Question 1
While a simple increase in fee per cattle has not worked in the past, stricter requirements for the use of space could be employed that mimic the recommendations for private land owners. For example, the use of more sustainable practices like burning woody plants, using grasses that hold water better, and managing the movement of herds to prevent overgrazing could all help prevent the tragedy of the commons on public lands.
Answer to Question 2
A particularly troublesome class of synthetic organics is the halogenated hydrocarbons, organic compounds in which one or more of the hydrogen atoms have been replaced by atoms of chlorine, bromine, fluorine, or iodine. Most of the so-called dirty dozen' POPs are halogenated hydrocarbons. All are toxic to varying extents, and most are known animal carcinogens. Many are also suspected endocrine disruptors at very low levels. Several of the organic compounds bioaccumulate in living tissue.
The skeletal system of a modern horse
The Ventricular System of the Brain
The two-system view of the stress response.
Development of the Digestive System "تطوير الجهاز الهضمي"
Circulatory System of a Shark
Muscular system