Answer:
1) Pentágono
2) Comés - Jovén - Débil - Necio (without accent)
3) Cantar Dental Ciudad (without accent) - Oración
4) PEZ, YO and SOL are monosyllable
5) ungüento
Explanation: I'm a Spanish speaker, so I'm very sure that those are the correct answers ;)
De que estamos hablando ?
Both say “it’s their store” it just depends whether you are talking about one or more people. Su is usually he/she but it can mean they/it if you are being non-gender specific. Personally I would go for Es sus tienda but I’m not a native Spanish speaker so I could be wrong