This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Environment and health, Subject name: Social & Preventive Medicine
Effect of radiation above threshold level - 
Select and explain. 
A. Stochastic effect, B. Non-Stochastic effect, C. Lethal effect, D. Genetic effect
B: Non-Stochastic effect
Answer: B: Non-Stochastic effect 
Explanation: park's textbook of preventive and social medicine 23rd edition *effect of radiation exposure are called somatic if they become manifest in the exposed individual and hereditary if they the descandants . *for some somatic effects ,the propability of an occurring ,rather than its severity ,is regarded as a function of dose without a theshold (stochatic effect).where as for other somatic effects the severity vary with doses (non-stochastic effect ):a threshold may therefore exist for such effects .