The WHO's primary mission is to promote health and well-being worldwide, with a focus on preventing and controlling diseases, promoting healthy lifestyles, and ensuring access to essential healthcare services.

The WHO's core functions include setting international health standards, providing technical assistance to countries, coordinating global health initiatives, and conducting research and disseminating health information. It does not directly provide healthcare services to individuals.

The WHO plays a comprehensive role in global health policy by developing and advocating for policies that promote health and well-being, monitoring and evaluating the implementation of health policies, and providing technical assistance to countries in developing and implementing health policies.

The WHO advocates for health policies through a combination of issuing policy statements and recommendations, working with governments and other stakeholders to develop and implement policies, providing technical assistance and capacity building, and raising awareness of health issues and promoting public engagement.

The WHO plays a central role in coordinating global health initiatives by bringing together countries and partners to address common health challenges, developing and implementing global health strategies and plans, and monitoring and evaluating the progress of global health initiatives.

The WHO conducts research and disseminates health information through a combination of conducting its own research studies, collaborating with other research institutions, and disseminating research findings and health information through publications, conferences, and other channels.

The WHO's role in promoting health and well-being encompasses promoting healthy lifestyles and behaviors, preventing and controlling diseases, and ensuring access to essential healthcare services.

The WHO promotes healthy lifestyles and behaviors through a combination of developing and disseminating guidelines on healthy diets and physical activity, working with governments and other stakeholders to create supportive environments for healthy living, and raising awareness of the benefits of healthy lifestyles and promoting public engagement.

The WHO prevents and controls diseases through a combination of developing and disseminating guidelines on disease prevention and control, providing technical assistance to countries in implementing disease prevention and control programs, and coordinating global efforts to combat diseases.

The WHO ensures access to essential healthcare services through a combination of working with governments and other stakeholders to strengthen health systems, providing technical assistance to countries in developing and implementing health policies and programs, and advocating for increased funding for health systems.

The WHO plays a central role in addressing health emergencies by coordinating global efforts to respond to health emergencies, providing technical assistance to countries in preparing for and responding to health emergencies, and developing and disseminating guidelines on health emergency preparedness and response.

The WHO works with governments and other stakeholders to promote health and well-being through a combination of providing technical assistance and capacity building, advocating for policies that promote health and well-being, and collaborating on research and development of health interventions.

The WHO collaborates with other international organizations to promote health and well-being through a combination of participating in joint initiatives and programs, sharing information and resources, and coordinating efforts to address global health challenges.

The WHO faces a number of challenges in fulfilling its mission, including limited funding and resources, political and economic barriers, and lack of cooperation from some countries.

Despite the challenges, the WHO has achieved significant successes, including the eradication of smallpox, significant reduction in the incidence of polio, and increased access to essential healthcare services.