Answer:
Insurance purposes.
it's where they grew up
sometimes it's better for agriculture
Explanation:
Can you please put your question in English?
Answer: seasonal turnover when water is it's most dense form it floats
making measurements of features and plotting them on a base map recording and sketching observations in a notebook collecting samples to take back into the lab paying special attention to diagnostic features, such as a fault.
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 :)