Uguys on r smart, me out (will be marking brainliest)
the part of a soil profile that is made up of partly weathered rock is the:

bedrock
subsoil
regolith
topsoil

it's the regolithhope this helps you

C Horizon - Also called regolith: the layer beneath the B Horizon and above the R Horizon. It consists of slightly broken-up bedrock. Plant roots do not penetrate into this layer; very little organic material is found in this layer. R Horizon - The unweathered rock (bedrock) layer that is beneath all the other layers.

i'm sure the answer you are looking for would be

a. an ice age

hope this contact me if this didn't or you need with more answers : )