Secularism, humanism, naturalism, and classicism are the defining characteristics of which european time period?.

experiments.

surveys.

questionnaires.

interviews.

case studies.

participant and non-participant observation.

observational trials.

studies using the delphi method.

"choosing is refusing" means individuals face an opportunity cost with each decision they make. economists state that every decision involves trade-offs. opportunity cost is the least desirable alternative given up as a result of a decision.

permafrost layer, it exists beneath a layer of soil, rock or sediment.

answer; elasticity of the lungs decreases;