Question 3 (Mandatory) (20 points) Why is it difficult to be extremely accurate with survival time from disease onset (i.e. calculating 5 year survival rates,etc.)? Check all that apply. (_) We don't always know when the biological onset of the disease occurs. (_) The creation of life tables complicates things. Counting the time from when signs and symptoms of disease begin results in subjective variability. The time from when the biological onset of the disease to when signs/symtoms begin can be variable (weeks, months, years)