Final answer:
Infectious diseases were unintentionally spread by imperialism through increased global interactions, affecting societies with no immunities to such diseases. The correct answer is option a.
Step-by-step explanation:
The concept in question is related to the unintentional consequences of imperialism, a form of foreign policy where one country extends its power over others, often through colonization, use of military force, or other means. Among the choices provided, the option that was unintentionally spread by imperialism is infectious diseases. Although not listed specifically in the multiple-choice options, it is clear from the historical context that infectious diseases were an unintended spread due to increases in global interactions, with imperialism as one of the contributing factors.
Modern science, nationalism, global economic connections, and industrialization were, by contrast, spread deliberately or developed as a result of imperialism. Diseases such as measles, cholera, smallpox, and bubonic plague were inadvertently spread through the travels and infrastructure established during imperial times, deeply impacting societies that had no natural immunities to these diseases.