Question

C. Answer the following questions very briefly.
1. Name the indirect sources of knowledge about the structure of the Earth.
2. What is the basis on which the Earth is divided into concentric layers?
3. Name the most abundant elements found in the Earth's crust.
4. What is the main feature of the secondary waves?
Guys this is from class 9 geo book.. chap 4 structure of Earth... plz answer ​

Answer 1

Indirect sources include meteors that at times reach the earth, gravitation, magnetic field, and seismic activity.

Answer 2

Answer:

1. the indirect source of knowledge about the structure of the earth are:

1. Temperature inside the earth,

2. Pressure inside the earth,

3. Density of different layer of the earth,

4. Behaviour of earthquake waves.