The answer to this is Plan a steady progression of exercise intensity.
A bacterial STDs are caused by bacteria that enters the body either through skin contact or body fluids. a viral std is a sexually transmitted infection that is caused by a virus. unlike bacteria viruses these are not living organisms and need a host cell in order to replicate and survive. some of the most common vital stds are HPV, herpes, hepatitis and HIV these cannot be cured however although a virus will remain in the body for life symptoms of the virus that might be not be present at all times.
I would go for B. Production of immune cells
The upper airways begin with the nasal cavity and continue over nasopharynx and oropharynx to the larynx and the extrathoracic part of the trachea
