Answer:
DNA. genetic material passed down generationa
I would assume the cause would be because organisms are growing almost from scratch. They lack many resources needed for survival and thus the changes occur slowly. The life forms also tend to be simple, such as plants.
Answer:
The human skull consists of 22 bones (or 29, including the inner ear bones and hyoid bone) which are mostly connected together by ossified joints, so called sutures. The skull is divided into the braincase (neurocranium) and the facial skeleton (viscerocranium). Its main task is the protection of the most important organ in the human body: the brain.
The brain is almost entirely enclosed by the neurocranium with the exception of the foramen magnum and other foramina at the skull base which serve as entry and exit point for blood vessels and cranial nerves. Also, the skull provides support for all of the facial structures.
Because an organism with a genetic variation may have better chances of breeding and passing on that trait if the trait is beneficial to the survival of that organism. This leads to that trait being passed on and becoming wide-spread over generations of reproduction; natural selection.
