4.
Sickle was a tool of the Neolithic age.
Stone on stone is a method of tool making.
Answers
A stone tool is, in the most general sense, any tool made either partially or entirely out of stone. Although stone tool-dependent societies and cultures still exist today, most stone tools are associated with prehistoric (particularly Stone Age) cultures that have become extinct. Archaeologists often study such prehistoric societies, and refer to the study of stone tools as lithic analysis. Ethnoarchaeology has been a valuable research field in order to further the understanding and cultural implications of stone tool use and manufacture.
Stone has been used to make a wide variety of different tools throughout history, including arrow heads, spearpoints and querns. Stone tools may be made of either ground stone or chipped stone, and a person who creates tools out of the latter is known as a flintknapper.