Answer:
Over the last two centuries the dipole strength has been decreasing at a rate of about 6.3% per century. At this rate of decrease, the field would be negligible in about 1600 years. However, this strength is about average for the last 7 thousand years, and the current rate of change is not unusual.
The correct answers are:
- Formation 2 is an intrusion;
- Formation 1 in an extrusion;
- Formations 1 and 2 are igneous rocks;
The formation one on this image is an extrusion, and the reason why it is an extrusion is that it has come out on the surface. The formation two on this image is an intrusion, and the reason why it is an intrusion is that it has formed deep into the ground.
Both of the formations will produce igneous rocks. The formation one will produce extrusive igneous rocks that will have very small crystals because of the quick cooling off of the magma. The formation two will produce intrusive igneous rocks that will have larger crystals because of the slower cooling off of the magma.
Answer:
Pollution is their biggest problem
