If you refer to the survival of something or someone, you mean that they manage to continue or exist in spite of difficult circumstances.
companies which have been struggling for survival in the advancing recession.
在不断恶化的萧条期中一直挣扎求生的各家公司。
If you refer to the survival of a person or living thing, you mean that they live through a dangerous situation in which it was possible that they might die.
If cancers are spotted early there's a high chance of survival.
如果癌症能再早期发现,存活的机率就高。