I believe it is D. International date line, because the question holds the answer. When you say "Different days" it kind of gives the answer away.
Hope this helps :)
Answer:
1.do the earthquake drill
2.help who is injured
Explanation:
that is my opinion ...hope it helps
2. Equal
The development of the countries does not really affect the population. Look at China. China is still very much underdeveloped compared to America, but yet it has 2x as many people as America and makes up 1/4 of the human population.