Answer: A compound is a substance in which two or more elements are combined together chemically.
Explanation: Elements present in a compound are always in a fixed proportion and can be separated only by a chemical method. For example, water is a compound composed of hydrogen and oxygen atoms in the ratio of 2:1. The chemical formula of water is H2O.
From the given options, the following sidovery involving DNA happened first: C) Griffith learned that a chemical changed harmless cells into harmful cells.
The British medical officer named Frederick Griffith discovered DNA in 1928 while conducting experiments using Streptococcus pneumoniae bacteria and mice.
<span>He concluded that the living R bacteria had been transformed into pathogenic S bacteria by an unknown, heritable substance from the dead S cells that allowed the R cells to make capsules.</span>
The answer is C) researchers employed by the environmental protection agency
A well mixed serial dilution is critical to achieving a homogenous mixture that has a constant concentration over the sample volume. If the dilution is not well mixed then it will affect the subsequent dilutions consent ration which will lead to percent error
