Wave energy remains constant as water depth changes.
        
             
        
        
        
When a tourist told him that each turtles look different on the island
        
             
        
        
        
The Moon appears to Earth as a small crescent, as it rotates around the Earth this expands to a full moon and back to a small crescent. This happens once every 29 days and is called a lunar month. The Moon causes the rise and fall of the ocean's tides on Earth.
        
             
        
        
        
Answer:
c) A study of how disease rates vary among different population groups
Explanation:
Epidemiology is the systematic and scientific study of the distribution of the health-related issue in a specified population.
The Epidemiologists studies the disease and its cause in a population by the collection of the data which gives an insight in the distribution of the health issues in the population living from a small area like school to a country.
The epidemiological studies help the society by reducing the risk of the negative health outcomes, in spreading awareness about the health issues and in framing the health policies.
Thus, Option-C is the correct answer.