That's commonly called a 'census'.
Demographics
sample is the population we make our study about them.
population dynamics-Population dynamics is the study of the factors that influence these changes in a population's size
This study is known as Mycology
The study of population change and distribution is demography.
Cross-sectional studies are also known as transversal and prevalence study. It is a form class of research methods that is all about population and the different case control studies that provide data on all the population that is under study.
Ecologist study population by mark and recaptur tagged and released.
The collection and/or study of coins is called Numismatics.
The statistical study of all populations is called demography. This study involves recording and taking data from things like the census to study items like the size, dispersion, income, etc. of a population.
Population dynamicstion…
the study of immunity is known as immunology.