Which one is correct and which one is suitable?

1. All lives are equal.
2. All lives is equal.
3. All life is equal.

My friend whose native language is English chose 1 for the first time but later he told me that 2 is better because ‘is’ here emphasizes the entirety.

I’m pretty confused because I only found usage ‘are’ online.

Question

Which one is correct and which one is suitable?

1. All lives are equal.
2. All lives is equal.
3. All life is equal.

My friend whose native language is English chose 1 for the first time but later he told me that 2 is better because ‘is’ here emphasizes the entirety.

I’m pretty confused because I only found usage ‘are’ online.

Answer

Life can be countable or uncountable, so number 1 and number 3 are both okay. Number 2 doesn't work because you have a plural noun with a singular verb.

ご自宅で快適に語学を学べるチャンスをお見逃しなく。経験豊富な語学講師陣の中からお選びいただき、今すぐ最初のレッスンにお申し込みください！