During the past 100 years, the major causes of death have shifted from to

During the past 100 years, the major causes of death have shifted from INFECTIOUS DISEASES to CHRONIC DISEASES.
About a century ago, most diseases were usually acquired by people as a result of infection, that is, the causative organisms are usually passed from one person to another. But since the advent of microbiology in medicine, the trend has change, because the microbes can now be countered using different antibiotic means.

The zone your looking for is the intertidal zone.