Question

it was once believed that diseases were transmitted through the air by something called miasma – a poisonous, foul-smelling vapor filled with particles of decomposed matter. what new evidence changed the scientific knowledge of disease transmission? the proposed theory of evolution by natural selection. the discovery of the structure of dna. the development of the principles of inherited genetic traits. the discovery of the existence of bacteria.

Explanation:

The question is about what new evidence changed the scientific knowledge of disease transmission. The miasma theory was replaced when bacteria were discovered as the cause of many diseases. The theory of evolution (A) is about species change, DNA structure (B) is about genetics, and inherited genetic traits (C) are about heredity, none of which relate to disease transmission like the discovery of bacteria (D) does.

Answer:

D. The discovery of the existence of bacteria.