How do frozen embryos live?

Frozen embryos are preserved at extremely low temperatures, usually between -196 and -320 degrees, in a process known as cryopreservation. 

This allows to stop the development of the embryo and preserve it in a viable state until it is thawed and used for a transfer in the uterus. 

Frozen embryos are usually stored in liquid nitrogen or in a specialized cryopreservation chamber, where they are kept at these extremely low temperatures.