Most buildings in the middle ages were made of

i confess that there are several parts of this constitution which i do not at present approve, but i am not sure i shall never approve them: for having lived long, i have experienced many instances of being obliged by better information or fuller consideration, to change opinions even on important subjects, which i once thought right, but found to be otherwise. it is therefore that the older i grow, the more apt i am to doubt my own judgment, and to pay more respect to the judgment of others.

what is the question

a. poison gas was sprayed over battlefields by airplanes to weaken enemy positions before major attacks.

    the answer is d hope this