Un is 'a,' masculine. Una is 'a,' feminine. Unos means 'some' or 'a few, ' masculine. Unas means 'some' or 'a few, ' feminine. That is just the answer. Enjoy
B
Cuando vamos a un concierto oímos música y hay personas que cantan o tocan instrumentos
When we go to a concert we hear music and there is people who sing or play instruments
5 makes the most sense since it’s asking for a birthday and the response is a date! :)
A, el cuello — the neck.
Which “connects the head to the body of the giraffe.”