Adjectives in Serbian - Part 6

While I am working on my new series of Serbian language courses, I prepared for you a video lesson with a bunch of adjectives, with the verb TO BE and forming simple sentences such as:

1. DA LI SI LEP/LEPA? - Are you beautiful?
2. DA LI JE ON UPLAŠEN? - Are you scared?
3. DA LI STE ZDRAVI? - Are you healthy?
4. DA LI JE TVOJ SIN GLADAN? - Is your son hungry?
5. DA LI JE TVOJA ĆERKA GLADNA? - Is your daughter hungry?
6. DA LI SU TVOJE ĆERKE GLADNE? -Are your daughters hungry?
7. DA LI SU TVOJI SINOVI GLADNI? - Are your sons hungry?
8. DA LI JE TVOJ AUTO STAR? - Is your car old?
9. DA LI JE HLEB JEFTIN? - Is bread cheap?
10. DA LI SU PSI STARI? - Are the dogs old?

Although I didn't write down my short answers, pay attention to them :)

JESAM - NISAM
JESI - NISI
JESTE -NIJE

JESMO -NISMO
JESTE - NISTE
JESU - NISU

For all of you who told me you LOOOOOVE my new cartoons, here's one covering this topic:

Your task is to figure out which word is missing?