A. seafloor spreading at mid-ocean ridges
Answer:
we need more from the question
Explanation:
The correct answer is - A) subsistence farming.
Subsistence farming is the type of farming that is mostly practiced in the less developed countries. In here we have production that is just about enough for the needs of the country (and big portion of the production doesn't even come out on the home market, but you eat what you produce, or trade with someone you know). Also this type of farming is still based on primitive tools and is heavily dependant on the climate, and that makes it very unstable and more often than not people are starving because not enough food has been produced.
