Questions & Answers about La mela non è rossa, ma è buona.
Can I use ma exactly like the English word "but"?
Why is there no Italian word for "it" in the second half of the sentence?
In Italian, you don't need to use subject pronouns (like he, she, or it) when it is obvious what you are talking about. Since we are already talking about the apple, we can drop the subject and just say è buona (is good).
Why do both adjectives end in "-a" (rossa, buona)?
Because they describe la mela (the apple), which is a feminine singular noun. In Italian, adjectives change their endings to match the noun they describe, so the default forms rosso and buono change to rossa and buona.