Ustedes means you all. if it was one teacher I would use usted because it is the formal version of you, tu
Tus, or the answer is option b
I think the answer is Self confidence
¿Dónde? Where?
¿Adónde? To where? , and
The Northern hemisphere consists of about 90% of the earth's land area.
The Southern hemisphere consists of about 90% of sea.
North has winter.
South has summer.