Final answer:
Health agencies, such as the CDC and WHO, are the best sources of data to determine the most prevalent and deadly diseases in a community. They collect data from various sources, including death certificates, disease surveillance systems, hospital records, and population-based surveys.
Step-by-step explanation:
In order to determine the most prevalent and deadly diseases in a community, the best sources of data would be health agencies, such as the Centers for Disease Control and Prevention (CDC) or the World Health Organization (WHO). These agencies collect data from various sources, including death certificates, disease surveillance systems, hospital records, and population-based surveys. By analyzing this data, they can identify the diseases that are most common and have the highest mortality rates.