Which of the following would have direct effects on the resources available to a population?

Hello!

You forgot to add any options! but I can answer the question more generally:

Natural resources, including food:

the major influence is weather and climate. For example a drought or a flood can destroy a year's harvest and cause famine.

Human resources: the infrastructure available, for example good university network could lead to reach human resources (many skilled workers).

Also the resources availalable to its neighbours, as they would determine what a given population can dtr