Read the text and choose the correct answer.
Drugs of animal origin include glandular extracts containing hormones, such as insulin for use in treating diabetes. Antibiotics, vaccines, human blood-plasma fractions, and steroid hormones are other important pharmaceuticals manufactured from natural substances. Vitamins, which were formerly obtained from natural sources, are now often made in the laboratory.
What substances can be produced in laboratory ways?

• vitamins
• glandular extracts
• steroid hormones
• human blood-plasma fractions