I believe it should match as the following...
sight in whales -----> eyeballs in cavefish
balance in monkeys -----> tailbone in humans
attachment point for limbs in frogs -----> pelvis bone in whales
Might be Cell Differentiation...
As diatoms are made from silica this makes diatomaceous earth very abrasive, and so the sharpness enhances the particles as a pesticide. Diatoms are also useful in forensic studies. If a person has drowned then diatoms are able to enter the human body.
Answer:
The molecule that would be affected by 'limited nitrogen' is the myofibrillar proteins in muscle. Explanation: The myofibrils of the muscle have a number of protein molecules.