、。
She failed the exam, but it was understandable.
Literal
She [topic-は] exam [target-に] failed [but-が], that [topic-は] understandable was.
The set phrase 無理もない (literally 'there isn't even unreasonableness') means 'understandable / natural / no wonder' — used to validate or excuse a result by suggesting it would be unreasonable to expect otherwise. Common in sympathetic comments after disappointing news. The clause-final が here is the contrastive 'but,' linking the failure to the softening evaluation. それは picks up the failure as the topic of the second clause — a useful demonstrative anaphor for referring back to a whole prior situation rather than a specific noun.