46. The author compares a scent molecule with a (A) key (B) lock (C) cell (D) bloodhound

2. What can be inferred from the passage about the agricultural sector of the economy after the Civil War? (A) New technological developments had little effect on farmers. (B) The percentage of the total population working in agriculture declined. (C) Many farms destroyed in the war were rebuilt after the war. (D) Farmers achieved new prosperity because of better rural transportation.