Answer:
The effectiveness of chemical disinfectants has historically been compared to phenol.
Explanation:
The effectiveness of a disinfectant or antiseptic can be determined in a number of ways. Historically, a chemical agent’s effectiveness was often compared with that of phenol, the first chemical agent used by Joseph Lister. In 1903, British chemists Samuel Rideal (1863–1929) and J. T. Ainslie Walker (1868–1930) established a protocol to compare the effectiveness of a variety of chemicals with that of phenol, using as their test organisms Staphylococcus aureus (a gram-positive bacterium) and Salmonella enterica serovar Typhi (a gram-negative bacterium). They exposed the test bacteria to the antimicrobial chemical solutions diluted in water for 7.5 minutes. They then calculated a phenol coefficient for each chemical for each of the two bacteria tested. A phenol coefficient of 1.0 means that the chemical agent has about the same level of effectiveness as phenol. A chemical agent with a phenol coefficient of less than 1.0 is less effective than phenol. An example is formalin, with phenol coefficients of 0.3 (S. aureus) and 0.7 (S. enterica serovar Typhi). A chemical agent with a phenol coefficient greater than 1.0 is more effective than phenol, such as chloramine, with phenol coefficients of 133 and 100, respectively. Although the phenol coefficient was once a useful measure of effectiveness, it is no longer commonly used because the conditions and organisms used were arbitrarily chosen.
The answer to the question stated above is letter C.
Observation of tool-making among chimpanzees was revolutionary primarily because scientists believed <span>tool-making was a defining characteristic of humans.
>>>FACT<<<
>C</span>himpanzee mothers in <span>the Tai Forest, </span>instruct their children in tool use. Chimpanzee mothers assist them in placing the nut in the anvil in the proper way.
Answer:
Hello! Trophic hormone is a hormone that has a growth effect, hyperplasia or hypertrophy, on the tissue, it is stimulating.
Explanation:
Hope this helps! :) -Jade231234
The answer is natural selection. Charles Darwin popularised
the term "natural selection". The change in the heritable traits
characteristic of a population over generations. Natural selection is reproduction
of individuals due to differences in phenotype and the differential survival It
is a key mechanism of evolution.