Mindy sees a famous physicist, Dr. Walker, on television. Dr. Walker says that there is no evidence to support the idea that humans are related to other mammals. Which of the following statements is true? A.

Mindy should reject Dr. Walker's statement because another physicist on television disagrees with him.

B.

Mindy should accept Dr. Walker's statement because he is a respected scientist.

C.

Mindy should accept Dr. Walker's statement because it was broadcast on television.

D.

Mindy should question Dr. Walker's statement because biology is not his area of expertise.

1.Griffith in his experiment used two related strains of bacteria (Streptococcus pneumonia), known as R and S and mice, trying to develop a vaccine against pneumonia. R strain-formed nonvirulent, rough-edged colonies  

S strain- rounded and smooth colonies, with sugar protection coat, virulent

Mice that were injected with S strain developed pneumonia and died.

But, when mice were injected with heat-killed S strain it did not cause disease in mice.

The next part of experiment is the injection of combined harmless R bacteria with harmless heat-killed S bacteria. The result was that the mouse developed pnenumonia and in blood sample from the dead mouse, living S bacteria were found.

2.From his experiment, Griffith concluded that injected together, R strain and S strain bacteria most likely “communicate”. The R-strain bacteria took "transforming principle" (we know today that this is genetic material DNA) from the heat-killed S bacteria which allowed them to "transform" into virulent bacteria.