Aunit of measurement that is obtained by combining other units is a unit

photos creat an ovveral image of the civil war

the  equal rights amendment  (era) states: "equality  of  rights  under the law shall not be denied or abridged by the united states or by any state on account of sex." congress first introduced the era in 1923, but the campaign for ratification took off in the 1960s during the  civil rightsmovement.

the steam engine.

the locomotive.

the telephone.

the telegraph.

the internal combustion engine.

the rifle.

ironclad ships.

electricity/light bulb.