First of all, an optical drive can be a CD, DVD, or BluRay drive. The button isn't invisible, it's just hidden in plain site by design. The previous pictures show its location, but here is one more. This is a picture of the top of a 660 showing 2 drives.
What is difference between an osteon and osteocyte? An osteon is the functional unit of cortical bone. Osteons contain osteocytes, which are cells that produce bone matrix.
Adorable animal families that will make you aww. The osteon is the primary structure that makes up the hard outer layer of bones, which is generally known as â cortical bone .â Cortical bone, or compact bone, is dense, mature bone found in vertebrates such as mammals, amphibians, reptiles, and birds.It is this dense hard layer that gives a person or animal strength.dorable animal families that will make you aww. The osteon is the primary structure that makes up the hard outer layer of bones, which is generally known as â cortical bone .â Cortical bone, or compact bone, is dense, mature bone found in vertebrates such as mammals, amphibians, reptiles, and birds.