1.каждый новая война приводит к более большим жертвам, чем предыдущий. какова причина этого? 2. какие обычно последствия после войны? 3.некоторые страны, например сша, имеют большую армию, другие маленькую армию, ещё некоторые, такие как швейцария и люксумбург не имеют армию вообще. какие преимущества и недостатки этого положения?

1.The reason of such situation is inventing of new weapon. The thing is that every year different countries spent a huge amount of money on developing of new and more poverfull weapon.The most dangerous weapon nowadays is nuclear weapon. If there is  the III World War, no one will survive.

2. There are many adverse impac after the war. Firstly, many dead people both: military and civil. Secondly, ruins instead of cities and villages. Thirdly, economic crisis. And these financial problems affect the overall well-being. Sothat is no work which mins starvation and more death.

3. In my opinion when country has a large army it gives more maneuverability. But when you have many people you can dispose of them without worrying vey much about the losses. I think it is a big disadvantage. Also the bad thing is that contries with big armies ussualy like wars and try to participate in many of them. Nowadays there two such countries USA and Russian Federation.
  Small armies. The disadvantage is the possibility of human losses. But as advantage here we can see a desire to save as many human lives as possible.
  No army at all. Plus - no human losses as a military at all. And if you have no army you  do not participate in war at least using people of your country. That is why ussualy countries without armies are impartial. But there are some disadvantages such as in case of the attack there is no one to defend the territory.