What usually attaches the kidneys to the retroperitoneum?

The region of the kidney between the capsule and medulla is called the renal cortex. 9

The T12 and L3 vertebrae attach the kidneys to the retro peritoneum.The areas between the renal pyramids are called the renal columns.

in 1859, charles darwin set out his theory of evolution by natural selection as an explanation for adaptation and speciation. he defined natural selection as the "principle by which each slight variation [of a trait], if useful, is preserved".