Translation:The animal laughs.
Is it laughs or smiles? The tool tip says both but if you enter smiles as an answer, it's wrong.
"usseumnida" is correct. Look up "Batchim pronunciation" to get a look at how the sounds between the final consonant and the following consonant change. It'll help you get an idea of how many words should sound while reading them.
You've already learned at least one of them. When ㅂ is followed by ㄴ it sounds like ㅁ