Is DO-DO an octave?

Please help its really easy

How does global media in the contemporary media landscape contribute to our perceptions of cultural identity domestic and foreign?

Acurator decides to display an eighteenth-century painting in a windowless room with controlled temperature and humidity. pick the answer that best describes the reasons for her choice: (1 point) 1)the curator wants to make sure that the temperature and humidity are comfortable for visitors. 2)keeping the temperature and humidity at a set level will save money. 3)the ultraviolet rays will damage the painting by fading and flaking the paint. 4)ultraviolet rays will fade the paint pigment and high temperature and humidity will damage the paint.

Riddle me this: i am first in earth,second in heaven,appear two times in aweekyou can only see meonce in a year, althoughi'm in the middle of sea.what am i?