Answer:
The Diagnostic and Statistical Manual of Mental Disorders, in its fifth edition (or DSM 5).
Explanation:
This a manual created and published by the American Psychiatry Association, which is used by most of today's psychologists for diagnostic related inquiries on mental health disorders.
Last updated, DSM 5, was published in 2013, and it is still consider as useful when seeking for statistic information.
Well, I am Russian, so you are getting this STRAIGHT from a source:
The two reasons were hunger and lack of medicine;
At that time, Russia's government were mostly dictators, and stole a LOT of food from the people, and a LOT of harvests & crops from the farmers for businesses;
Medicine was EXTREMELY expensive, and of course, the soldiers were treated WORSE than the people..........
So when they called for donations, the citizens BARELY were able to support themselves, so there was almost NOTHING to give to the soldiers!
Now, there were SOME food and medicine saved for soldiers, but it rationed QUITE QUICKLY!
So MANY soldiers were ill really fast, but due to the VERY skillful and useful techniques they learned to fight in the war, they still survived, (of course, there were soldiers who died too, but a MAJORITY of the Russians won).
I hope I helped, and PLEASE choose my answer as the Brainliest!
Thank you! =D
The last sentence because it already stated that it has a pattern of bad weather.