Louis pasteur developed the germ theory of disease, which states that many diseases are caused by microorganisms. had scientists been skeptical but not open minded about the idea,

Had scientists been skeptical but not open minded about the idea,it would not have become scientific consensus.

Explanation:

The germ theory of diseases was logically proposed by Louis Pasteur and  between the 1860 and 1864 he performed series of experimentation to prove the relationship between diseases and germs.

Main postulate of germ cell theory:

The main postulate of germ cell theory was this that infectious diseases are caused by microbes or small organisms that invade the organisms and make him sick.

Was it accepted at once by scientists?

The germ theory was not accepted at once by all scientific communities because there were contemporaneous of this theory. Some scientists said that inner condition of a person’s cellular body actually determines whether he will suffer from disease or not. Others said that Every disease is associated with a particular condition or the diseases are caused due to unhealthy life style and many others.

How was it accepted:

It was by the middle of 1800s when the germ theory started getting acceptance from majority of scientists worldwide. This was because several experimentation were made around the world which proved that physical existence of germs is mandatory agent for the spread of diseases. During 1890s, viruses were also discovered and therefore a "golden period" of bacteriology started, which led to the approval of germ theory by scientists around the word and it became an accepted theory.

Coming towards the answer of question:

If the scientists always stayed skeptical and not open minded about the germ theory, it would never have gained acceptance and scientific consensus.

Hope it helps!

the answer is "a.) well–developed vascular system."

explanation: