Ответ:

Союзная конструкция the more …, the more … означает: «чем …, тем …».

  1. the more fruit and vegetables — f) the healthier we are;
  2. the warmer and wetter the climate is — d) the better plants grow;
  3. the more water we waste — e) the worse it is for the planet;
  4. the more people travel — a) the more they learn about the world;
  5. the longer you stay in the hot sun — j) the more dangerous for you it is;
  6. the friendlier you are — b) the more people like you;
  7. the more we watched the game — h) the less we believed our team could win;
  8. the more we know about English-speaking countries — c) the more interesting it is to learn the language;
  9. the more we study the history of people — i) the more interesting facts we learn;
  10. the more paper we use — g) the more trees we have to cut down.