18. "taking safety measures of prevent disaster"
b. conventional
a. approaches
c. precaution
d. radio station
19. "to change to a liquid, usually because of heat"
a. glaciers
b. atmosphere
c. melt
d. greenhouse gases
20. "to store or keep a lot of supplies in advance"
a. safety kit
b. stockpiling
c. drinking supply
d. dehydrated