I believe it the answer is B. Men made the tools and hunted for food. I hope this helped.
Choice B. A strong theme can be applied elsewhere beyond the scope of a single story in which it appears.
The answer is "variable-ratio schedule".
In operant conditioning, a variable-ratio plan refers to a calendar of fortification where a reaction is strengthened after an eccentric number of reactions. This timetable makes an enduring, high rate of reacting. Betting and lottery diversions are great cases of a reward in view of a variable ratio schedule.
Many developing countries from Middle East to South America have attempted to master the process of development but have failed.
And one of the major reasons behind this is "Domestic Monopoly Power." Most of these countries are trapped in their local markets and do not open their markets internationally.
Domestic group interests have small incentives to open up their markets to international firms with advanced technologies.
However, if they even try to open their borders, they still remain trapped in low or middle levels of income.That's why poor countries remain poor over the period of time.
