Final answer:
Communicable diseases are the major cause of mortality in the least developed countries of the world.
Step-by-step explanation:
The major cause of mortality in the least developed countries of the world is communicable diseases. These diseases are caused by pathogens such as bacteria, viruses, and parasites, and can be transmitted from person to person or through contaminated food, water, or vectors like mosquitoes or ticks. Communicable diseases such as malaria, HIV/AIDS, and tuberculosis are more prevalent in these countries due to limited access to healthcare, poor sanitation, and poverty.
Learn more about Causes of mortality in least developed countries