Which of the following is considered an advanced, ex situ conservation of biodiversity?

Cryopreservation of gametes of threatened species in viable and fertile condition can be referred to as advanced ex situ conservation of biodiversity. In ex situ conservation, threatened animals and plants are taken out from their natural habitat and placed in special setting where they can be protected and given special care.

In recent years ex situ conservation has advanced beyond keeping threatened species in enclosures. Now gametes of threatened species can be preserved in viable and fertile condition for long periods using cryopreservation techniques. It involves preservation at -196^oC in liquid nitrogen. It can maintain tissue culture, embryos, animal cells/tissues, spermatozoa indefinitely. The cryopreserved material is revived through special technique, when required.