According to Darwin, Competition refers to the struggles that living organisms have to face on day to day basis in order to obtain enough resources (such as food and water) To survive.
- Overproduction
Charles Darwin stated that overproduction is organisms' tendency to produce more offspring than what they could realistically sustain. Darwin believe that they did this because there is always a chance that the offsprings might got killed and unable to obtain food before they can reproduce again. Overproduction ensure that their genetic line can continue for as long as possible.
- differential reproduction
Darwin believe that organisms have a tendency to reproduce with other organism if they have a certain unique characteristics that help them survive. (Such as more strength, better beak shapes, Longer necks, etc)
Theory of macroeconomics which dominated the Reagan administration was supply-side economics. The answer to your question is D. I hope this is the answer that you are looking for and it comes to your help.