to visit its world-famous cities
Answer:
Youngest: Niger
1. Niger — 50.12% under 15.
Oldest: Japan
Japan has the highest old-age dependency ratio of all OECD countries – there is one person over 65 for every two people between the ages of 20 and 64.
Explanation:
Helpful:
Cures for disease's
Helps us learn about everything around us.
Harmful:
Chemical Warfare
New atomic bombs etc...
That it would take light 7.4 years to travel through space.
