Answer:
every 100,000 to several million years
Explanation:
This is the closest option. .
The last happened about 780,000 years ago and is called the Brunhes–Matuyama reversal.
Answer:
A. True
Explanation:
Oceanic crust, while older than plateaus of rocks found far away from volcanic activity, it is much thinner, denser, younger, and of different chemical composition than continental crust. Continental crust is typically 30-50 km thick, whilst oceanic crust is only 5-10 km thick. On the other hand, plateaus of rocks are formed from volcanic activities and are of more recent occurrence than oceanic crust.
It is a completely false statement that generally, the compaction of soil is a positive phenomenon. The correct option among the two options that are given in the question is the second option. It is hard to work and manage such type of soils. The loose soils absorb water and minerals very easily, while compacted soil is derived of pores and so absorption is difficult.<span />