Immigrants come to these two north american countries because of their high standards of living.
1. canada
2. greenland
3. mexico
4. u. s.

What causes the cycle of seasons on earth? the tilt of earth’s axis the shape of earth’s orbit the direction of earth’s orbit the distance between earth and the sun

What major factors play a role in global warming? 1. human activity and normal climate conditions 2. natural factors and human activity 3. normal climate conditions and abnormal human activities 4. abnormal human activities and natural factors

Simple astronomical telescope the objective lens has a focal length of 75 cm and that of a piece of 5cm of the lenses are 18 cm apart when will be final image of a distant object before