Certain preparations contain killed or weakened live biological agents that, upon injection into our body, protect the body against those pathogens. what are these preparations called?

relative humidity, temperature and dew point -- are bound together in the mathematical relationship below. relative humidity changes when temperatures change. because warm air can hold more water vapor than cool air, relative humidity falls when the temperature rises if no moisture is added to the air. so i would say a

in 1859, charles darwin set out his theory of evolution by natural selection as an explanation for adaptation and speciation. he defined natural selection as the "principle by which each slight variation [of a trait], if useful, is preserved".

it's diluted or concentrated

in a diluted solution, you can add a lot more solute but in concentrated only a little more can be added