The answer is B. Population
Explanation:
They intend to use a formal method of investigation to determine which container is better. They are going to make a list of pros and cons for using each type of ... including sub-niche 1 or different task you do , sub-niche 2, and sub-niche 3. ... introduction that unexpectedly leads not to the theme, but to the first variation a ...
Pigs I believe because we take organs from them to perform transplants