Domande riguardo a frasi esempio con, spiegazione d'utilizzo di "Immortality"s

A: it means to never die

A: Do you believe in the immortality of the soul?

It was in the power of the gods to confer immortality upon mortals.

I once had the choice between absolute power and immortality.

A: × If human beings have the technology to achieve immortality, it won't be too difficult for them to move to a habitable planet, so I think the possibility of the earth being overrun with people is small.
✓ If human beings had the technology to achieve immortality, it wouldn't be too difficult for them to move to a habitable planet, so I think the possibility of the earth being overrun with people is small.

I think "had" and "wouldn't" may sound a little bit better because the discussion is about a hypothetical situation.

Everything else you have written looks great! 👍

A: １：People have long dreamed of immortality and eternal youth.
２：Everlasting youth and long life are the dreams of human beings. Indeed it seemingly sounds great, but if this ever became a reality, only unimaginable agony would await us.

Or "became a reality, unimaginable agony is all that would await us."