What do you mean? What species?
Answer:
D. a cause that directly leads to a normal condition without interference
Explanation:
Direct contact infections spread when disease-causing microorganisms pass from the infected person to the healthy person via direct physical contact with blood or body fluids.
Yes, Avery, Mc Leod and Mc Carty do thought that genes may be involved in the transformation of non virulent rough Strains of <em>Diplococcus pneumoniae</em> to harmful smooth strained bacteria
<h3><u>Explanation:</u></h3>
Avery was a Canadian medical researcher who along with other two well known scientists of the contemporary time went for an experiment where he took two strains of bacteria Diplococcus pneumoniae - one is rough and nonvirulent and another is smooth and virulent. For a control run, he injected both the bacteria in separate mice and the expected result was there. Now as he injected heat killed smooth bacteria, the mice survived. But as he injected heat killed smooth bacteria with rough bacteria, although there was no organism which can kill the mice the mice died. And autopsy revealed the presence of live smooth bacteria in the lungs.
Thus they suspected something have gone from the dead smooth bacteria into the non virulent rough bacteria which lead to transformation of the rough bacteria to smooth ones. Thus, the experiment was carried on, which suspected role of genes in this transformation.
Because we have smelled them so long we are used to them
