In general, most of us are susceptible to conformity and meeting group expectations. in so doing, what two things do we generally follow?

Two things that generally follow would be: prescriptions and proscriptions

In social group, prescription refers to something that authorized/allowed within that social group, and proscription is something that banned or deemed as inappropriate within that group

The one that most represents the earths mantle would be the skin since the mantle is the upper part of the earths depths which is just like the skin of an apple.