In the 19th century, Gregor Mendel performed a series of experiments on pea plants that led to the establishment of the field of genetics. He determined that genetic information is passed from a parent to its offspring during reproduction. He did not know how this information was stored or transmitted from one organism to another. Almost 100 years later, Oswald Avery did experiments on mice using virulent pneumonia and discovered that the transmission of genetic characteristics from parent to offspring is done through the inheritance of DNA molecules.

A few years after Avery determined that DNA was the molecule used for the storage and transmission of genetic information, James Watson and Francis Crick used data from X-ray studies to create an accurate model of the structure of DNA.

Based on the paragraphs above, it can be concluded that
A.
once a scientific theory has been established there cannot ever be any new scientific research done on the subject.
B.
over time scientific knowledge is reevaluated and extended through new scientific research.
C.
scientific research is always done separately and independently of all other scientific knowledge.
D.
scientific knowledge has not changed at all over the past two centuries.