PPSC Past Paper Assistant Director Punjab Employees Social Security Institution (PESSI) 2019 Solved MCQs, Everyday Science MCQs, PPSC Solved Past Papers MCQsWhich one of the following can be used to focus sun light?A. Plane mirror B. Concave lens C. Concave mirror D. Convex mirror Study of ancestors, family history and tracing their lineage is called?To observe a human behavior by living a natural setting is called?
