“Countries grow at different rates because they accumulate capital at different rates.” Is this true?

Explain your answer
On the use of maths: the essay should be mostly in English, even though a lot of it will
inevitably use technical (macroeconomic) vocabulary. Mathematical expressions should
be used sparingly. Yes, they can be very useful to support or make a verbal argument more
precise, but they are not a substitute for verbal explanations. If your essay contains a lot
of maths and few words, you should rewrite it. And do not assume the reader knows the
notation being used