Sentence construction: Humanity will be the cause of its own extinction?

[Carvalho]

Can we say: Humanity will be the cause of its own extinction?
Or should we say: Humanity wil be the cause of their own extinction.

And also can we say Human kind when we are speaking of the human race?

And if we use humankind, can we say: Humankind accepts the problems. Or : Humankind accept the problems. How do we use the verb?

Thanks!!

[Peterkua]

Humanity is a singular noun that means "all human beings collectively", so the following is correct:

Humanity will be the cause of its own extinction

Similarly, humankind is also a singular noun that means "human beings collectively", so we use a singular verb for it, ie. "accepts"

And yes, you can use humankind when referring to the human race

Peter Kua

[Carvalho]

Thanks for your explanation!!