Eleven-year-old evan was asked by his math teacher, "if adam is older than bill and bill is older than cathy, who is the oldest? " this question was too abstract for evan, and he was unable to answer. this shows that evan is in which stage of development?

This shows that Evan is in the concrete operational stage of development.

Explanation: in the Piaget's theory of development, the concrete operational stage is the stage when a child is within the age of 7 - 11 in which they develop logical thinking.

The question asked by the maths teacher requires logical reasoning to answer and typically, children in the concrete operational stage have not developed fully logical reasoning.

trade regulation is a field of law, often bracketed with antitrust (as in the phrase “antitrust and trade regulation law”), including government regulation of unfair methods of competition and unfair or deceptive business acts or practices. antitrust law is often considered a subset of trade regulation law. franchise and distribution law, consumer protection law, and advertising law are sometimes considered parts of trade regulation law.

in general the theory of economics says that the more open to trade a country is the better   the result for the same country and the whole economies.

in real life countries impose taxes, quotas, etc which is not so good for the economies.

this kind of commercial war between the usa and china is slowing down the growth of the whole world so we can say that it is a draw back of trade regulations. and the free trade agreements are benefits of trade regulations.