Answer:
a) recovered from pituitary glands removed from human cadavers.
Step-by-step explanation:
- The human growth hormone is responsible for growth along with cellular proliferation and reproduction in humans.
- The hormone is secreted by the pituitary gland.
- Therefore, before the recombinant DNA techniques were available the hormone was isolated from the pituitary glands fo human cadavers.
- However, this method was not continued because the extract hormone became a source of infection for diseases such as the Creutzfeldt-Jakob disease.
- Therefore, alternatives were looked for and with the advent, in recombinant DNA techniques, the scientist was able to successfully make the recombinant human growth hormone as well.