Answer: d. Extracellular matrix was discovered more than 20 years ago.
Explanation:
According to biological sciences, the extracellular matrix is a matrix that consists of three dimensional network of extracellular macromolecules such as enzymes, collagen and glycoproteins which provide structural and biological support for surrounding cells as well.
It is found that it is discovered over 20 years ago in the matrix formed in the mouse EHS sarcoma. Therefore, correct answer is (d).
