What are the easiest NORTH AMERICAN countries to do in Geoguesser explorer mode

An object weighs 40n in air , weighs 20n when submerged jn water and 30n submerged in a liquid of unknown density .what is the density of the liquid?

The specific department of health and human services (hhs) regulations that apply to research with children are known as: subpart b: additional protections for children involved as subjects in researchsubpart a: the common rulesubpart d: additional protections for children involved as subjects in researchsubpart c: protections for children in research

The process of rocks breaking down and becoming other rocks