People have also made huge changes to other natural vegetation regions. ... As you read in Chapter 2, human activities are contributing to climate change. Changes in climate are causing changes in vegetation patterns around the world. For example, rising temperatures are causing many plant species to migrate.
A) <span>the crust of the lithosphere that has fractured along plate boundaries and ridges</span>
The answer is b because the other ones are involved in environmental science
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.