Which of the instruments/ devices above will you use in the following situations?

16. You want to see closely the aurora of stars in the sky.

17. Father wants cost efficient vehicle that is also environmentally friendly.

18. Mother is planning to save some money from electric bill. Laurus

19. A seaman wants to explore the things above water as the submarine is travelling in the sea.

20. The family wants to celebrate the yuletide season with gleaming lights.​