1. Food (1) plays an important part in the development of nations.

   • The verb "plays" fits here as it suggests that food has a significant role.

2. In countries where food is (2) scarce, people have to spend most of their time getting enough to eat.

   • "Scarce" fits well here because it describes a situation where food is not abundant.

3. This usually slows down progress, because men have little time to (3) devote to government, and art.

   • "Devote" fits here as it means to dedicate time to something.

4. In nations where food is (4) plentiful and easy to get, men have more time to spend in activities that (5) lead to progress, human betterment, and enjoyment of leisure.

   • "Plentiful" describes an abundance of food.
   • "Lead to" suggests that these activities result in progress.

5. The problem of (6) providing good food for everybody has not yet been solved.

   • "Providing" fits well here because it means to supply or make available.

6. Many wars have been fought for the (7) control of rich food-producing lands.

   • "Control" is the appropriate word because nations often fight for dominance over valuable resources.

7. But it is no longer (8) necessary to go to war for food.

   • "Necessary" indicates that it is no longer required to engage in war for food.

8. Nations are beginning to put scientific knowledge to work for a (9) solution for their food problems.

   • "Solution" is the right word as it refers to solving food-related issues.

9. They work together in the Food and Agriculture Organization of the United Nations (FAO) to help hungry nations (10) produce more food.

   • "Produce" fits here as it refers to growing or creating food.

1. Without transportation, our modern society could not (11) exist.

   • "Exist" is the correct word because it means to be or live.

2. We would have no metals, no coal, and no oil (12) nor have any products made from these materials.

   • "Nor" connects the idea of lacking raw materials and products made from them.

3. (13) Besides, we would have to spend most of our time (14) raising food and the food we would have would be limited to the kinds that could grow in the climate and soil of our own neighborhoods.

   • "Besides" is an appropriate conjunction to add more information.
   • "Raising" fits here as it means cultivating or growing food.

4. Transportation also (16) affects our lives in other ways.

   • "Affects" is the right word as it indicates the impact of transportation on our lives.

5. Transportation can speed a doctor to the (17) scene of a sick person, even if the patient lives on an isolated farm.

   • "Scene" is appropriate as it refers to the location of an event.

6. It can take police to the (18) scene of a crime within moments of being notified.

   • "Scene" fits again as it describes the location of the crime.

7. Transportation (19) enables teams of athletes to compete in national and international sports contests.

   • "Enables" fits as it means to make possible.

8. In times of (20) disaster, transportation can rush aid to persons in areas stricken by floods, famines, and earthquakes.

   • "Disaster" is the right word as it refers to events like floods and earthquakes.

Let me know if you need further explanation or help with other tasks!