Because American unions were instrumental in pushing for increased protective legislation such as workers' compensation laws and unemployment insurance, the demand for union services has increased, rather than decreased, over time.

Which vertebrae contain transverse foramina?

A) Thoracic vertebrae only
B) Lumbar vertebrae only
C) Cervical vertebrae only
D) Cervical and thoracic vertebrae
E) All vertebrae in the vertebral column contain transverse foramina.

The length of time needed to eliminate half of a dose of a hormone is called its ________.