The correct answer is A. Gene bank.
A gene bank is a facility that stores genetic material, such as seeds, tissue samples, and DNA, for the purpose of conservation and research. Gene banks play an important role in protecting endangered species by ensuring that their genetic material is available for future use.
A gene library is a collection of DNA sequences that have been cloned into a vector, such as a plasmid or a virus. Gene libraries are used to study the genomes of organisms and to identify genes that are responsible for specific traits.
A gene pool is the total genetic variation within a population of organisms. Gene pools are important for the long-term survival of populations, as they provide the genetic diversity that is necessary to adapt to changing environmental conditions.
A herbarium is a collection of dried plant specimens. Herbarium specimens are used for research and education, and they can also be used to identify and track the distribution of plant species.
In conclusion, the correct answer is A. Gene bank. Gene banks play an important role in protecting endangered species by ensuring that their genetic material is available for future use.