Translation:The shop was closed in two thousand and ten.
The shop closed v the shop was closed. The latter suggests that it was forced to closed or someone deliberately closed it. The former suggests the shop closed voluntarily. There is no context in the question so both should be accepted. Sorry to be pedantic but we're seeing this more and more. I have reported this by the way - I just wanted to see what others think
Gaeth y siop ei chau is literally "had the shop its closing", which is how Welsh expresses the passive. "The shop closed" would be caeodd y siop or gwnaeth y siop gau.
The Welsh sentence suggests that someone deliberately closed it as well, and probably the reason you're seeing more of it is that you're seeing more passive sentences. The context is that the Welsh sentence is passive - so it really should be translated with the English passive. The Welsh passive is explained in the Tips and Notes for TheNews: https://www.duolingo.com/skill/cy/TheNews
Duolingo works by teaching you both vocabulary and grammar through various sentences - hence why a lot of them are nonsensical, but still useful. This is meant to teach you to use vocabuary like cau, nwy fil a deg - and the grammar of the passive, which comes in useful when you need to say "the lamb was eaten".
The meanings of "the shop closed" and "the shop was closed" are close, but they use different grammar in both languages, which would make an enormous difference for other sentences. Allowing both translations for both wouldn't do anything to help people learn the passive form.