What is rift valleys and block mountains? What are their characteristics and how they formed?

Rift valleys are Formed  from either from the action of tensional forces in the crust or from the action of compressional forces!

And they move due to the force of gravity!

The block mountain (horst) is left standing higher above the sunken graben!

radiative zone

explanation    

radiative zone is the layer of the sun which energy is transferred away from the core by radiation. although, the core is the only part of the sun that produces an appreciable amount of heat through fusion. in fact, 99% of the energy produced by the sun takes place within 24% of the sun's radius.

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