The correct option is C Floating ribs in humans - 4
The phrase floating rib refers to the two lowermost, the eleventh and twelfth, rib pairs(so 4 bones); so-called because they are attached only to the vertebrae–and not to the sternum or cartilage of the sternum.
Diabetes mellitus is classified into four broad categories: type 1, type 2, gestational diabetes, and other specific types.
The cervical vertebrae of the spine consist of seven bony rings that reside in the neck between the base of the skull and the thoracic vertebrae in the trunk.
There are 20 amino acids.