Which was a characteristic of serfdom in the Middle Ages order to work.​

. Serfs had to sign a contract in order to work

the of atp are the key to its ability to store and supply energy;

phosphate

the phosphate groups of atp are the key to its ability to store and supply energy. atp releases energy when it breaks bonds between its phosphate groups.

to unite muslims and hindus in resistance against british colonialism.