Air and water

[edmondjanet]

Air and water is most essential in our life
Butter and milk is most essential in our life
In my knowledge 'are" is the correct but here one grammer book says "is" is the correct. Actually which one is correct

[Raymott]

Air and water is most essential in our life
Butter and milk is most essential in our life
In my knowledge 'are" is the correct but here one grammer book says "is" is the correct. Actually which one is correct

"Are" is correct.
How does your grammar book explain that "is" is right?

PS: Is this the same grammar book you refer to under your "Degree" thread? If so, I'd seriously consider either i) not using it or ii) finding someone who can explain how you're misreading it.