it is or they are

Question

1. We need a warm-kind heart and self-acceptance because it is the key to our success.
2. We need a warm-kind heart and self-acceptance because they are the key to our success.

Which is correct? "It is" or "they are"?

Answer 1

You are mentioning

1) a warm heart
2) self acceptance

since they are two separate things, the verb needs to be plural

We need a warm-kind heart and self-acceptance because they are the keys to our success.