<span>To determine population size one must have an effective way to count individuals in a given area. This can be challenging since individuals move and may be accounted for multiple times, therefore skewing the final results. Population density requires one to also calculate the area in which the population resides. This is relatively simple to do, but if individuals then exit or enter the calculated area, then the population density changes.</span>
Pressures can change the state of an environment – e.g. water quality reductions – which then causes impacts such as the loss of biodiversity and ecosystem services provision.
Avoid carcinogens (like smoking residues..etc), eat healthy and sleep well in order to maintain a strong immune system
please elaborate what u mean