Feel the back of your skull. Go ahead, feel it! You may feel a small bump, below which is an opening where the spinal cord enters your skull. The relocation of this opening toward the bottom of the skull is significant in evolutionary biology. Why

It occurred as a result of change to a bipedal stance.

Explanation:

Bipedal stance means an organism moves with the help of its two rear limbs. The evolution of humans have been in centuries where they learned to move using their two rear limbs only. It distinguishes humans from four limbed apes. This is by big brains which are  used by hominids. The hominids forms the largest part of the brain.

eukarya because is is like alche and b is bacteria and d is animals

explanation:

the second type of galaxy is called a barred spiral, which has a thing called a bar straddling the nucleus