Why is the Cristae folded inward?

The previous answer is not quite accurate. There's 2 answers to this question, depending on how advanced a level you are studying mitochondria on. Most biology courses at school will teach that the inner mitocondrial membrane is folded into finger-like protrusions called 'cristae'.

This is a trait found in many different parts of cells and tissues, and in this case it can be attributed to increasing the surface area of the inner membrane. This is important because the large complexes that make up the Oxidative phosphorylation pathway are embedded in this membrane. It will also increase the volume of the intermembrane space, but I don't think that is the appropriate way to view it.

There are many ways of increasing the volume of the intermembrane space, for example by increasing the size of the outer membrane. It is important to remember that the outer membrane is very permeable, and therefore the intermembrane space is very similar to the cytoplasm. Also, the proton-gradient ... more.

I cant really gove you an answer,but what I can give you is a way to a solution, that is you have to find the anglde that you relate to or peaks your interest. A good paper is one that people get drawn into because it reaches them ln some way.As for me WW11 to me, I think of the holocaust and the effect it had on the survivors, their families and those who stood by and did nothing until it was too late.