The division of labor occurred as surplus food supplies provided people with greater stability and security. This development enabled societies to become more sophisticated and to develop culturally. Complex social classes emerged; many social classes developed, including a ruling nobility and a priestly class. Other classes, such as artisan classes, developed based on skills. Organized religion also emerged. Religion was commonly polytheistic, initially with gods who focused on basic human desires and fears like fertility, death, and the weather. Recordkeeping and the first writing systems were other developments. Governments and tax collection came into existence, and cities organized military units and created military structures, such as moats, to protect themselves from invaders.
Secondary economic activities involve the processing of raw materials (primary products). Examples would include turning timber into furniture and turning iron-ore into steel. Any factory can be seen as a system involving inputs (e.g. timber) processes (e.g. cabinet making) and outputs (e.g. tables and chairs).
The correct statement is: All sedimentary rocks contain weathered rock and sediment. Sedimentary rocks are formed by material that has been removed from other rocks by weathering and which has been deposited in the place and became a rock by the process called sedimentation .