The combined genetic information of all individuals in a population is called the ...

• A. Gene pool
• B. Population density
• C. Immigration
• D. Symbiosis

Answer: (A)

This question tests understanding of what scientists mean by the genetic makeup shared by all members of a population. The combined genetic information of all individuals in a population is called the gene pool. It includes all the genes and all the alleles present within that population, representing the available genetic variation that natural selection and other evolutionary forces can act upon. A larger, more diverse gene pool provides more potential paths for adaptation, while events that reduce variation—like bottlenecks or inbreeding—shrink the gene pool and can limit evolutionary options.

Population density is about how many individuals occupy a given area, not about their genetic content. Immigration refers to individuals moving into a population and can alter allele frequencies through gene flow, but it describes movement rather than the overall set of genes in the population. Symbiosis is the interaction between different species, not a description of the population’s genetic reservoir.