definición de: Frecuencia cardiaca basal, Frecuencia cardiaca en reposo y frecuencia cardiaca en actividad

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

In a hydrogen molecule there are a total of four charges, 2 protons in the two nuclei, and 2 electrons. how many unique charge-pairs are there (without double counting)?

Which is gerrymandering a problem for the house of representatives but not the senate? a.) members of the house are greatly influenced by their political parties. b.) senators serve longer terms than members of the house. c.) members of the house are more influenced by changes in public opinion. d.) senators are elected in statewide elections rather than in specific districts.