Answer:in
Effect of small numbers of individuals on changes in the frequencies of an allele
Explanation:
By definition population genetics studies the changes in genetic variation of a population, this involves the modelling of changes in the frequencies of genes and alleles.
For example if an organism is born with a color that enhances its reproduction that population may change drastically in appearance, on the contrary if the allele causes a genetic disease, the population numbers might decrease.
Well, since its about it needing to survive and reproduce in a specific environment, it should be fitness.
Pseudo vacuoles are not true organelles since they are just air bubbles which do not possess tonoplast and cell sap like real vacuoles. But they do help by increasing buoyancy of cells.