Air and water is or are necessary for life.​

Air and water are necessary for life.

Explanation:

Air and water are a plural subject because a subject made up of nouns joined by 'and' makes a compound  subject, unless that subject's intended sense is singular, therefore the verb must be conjugated in the plural: "They are".

because most jews were in the concentration camps and dying horrible deaths while anne could be with her family in a warm place with shelter, food, water, and a place to sleep.