Answer:
Countries trade with each other when, on their own, they do not have the resources, or capacity to satisfy their own needs and wants. By developing and exploiting their domestic scarce resources, countries can produce a surplus, and trade this for the resources they need.
They are developed countries because the people there are healthy and educated.
It can be one of two things.
First, it can be due to global warming.
Second, it can be due to the rotation of the sun. When the sun rotates, it can change it latitude causing it to hit at different points onto different areas of the world.
Answer:
In SI units, G has the value 6.67 × 10-11 Newtons kg-2 m2.