I believe you meant to say is this mistake called a base pair and if that is your question then no. it would be called Mutation. But you can double check that answer.
I think the correct answer from the choices listed above is option A. It is the alveoli that is composed of single layer <span>surrounded by a network of capillaries. These are used to allow oxygen and carbon dioxide to move from the lungs to the bloodstream.</span>
A) after 1911 gradual increase in deaths pattern explains that smoking causes cancer !
b) after 2001 , the graph will continue decreasing, because of the steps taken by government, the steps by people itself !! that all helps in decreasing deaths and cancer number after 2001 !
