The primary source of colonial productivity growth in agriculture was:
a. learning by doing.
b. an increased capital-labor ratio.
c. technology improvements.
d. the introduction of hybrid seeds and fertilizer.

Answer is A. Learning by doing.

Explanation:

In the far olden days, during the colonial era, the farmers only improve on their productivity through the process of doing it. This involves trial and error process. It is so because, there wasn't technology and no form of modern education that will help them to carry out research before execution, they only depend on their instincts. This means that, they execute what they think and learn from it.

answer; (you have the right of way);