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.
Explanation:
Tho i can see no arrow but there is probability of 75% that a fourth child suffers the disease of the parent
Answer:
a) codominance
Explanation:
Codominance occurs when both the alleles of a gene are expressed equally in heterozygous genotype. Here, none of the alleles of a gene masks the expression of the other. It is one of the deviations of Mendel's law of dominance and gives three different phenotypes in the F2 generation of a monohybrid cross.
For example, ABO blood type in humans is regulated by three alleles of a gene. The alleles I^A and I^B are codominant and are equally expressed in the genotype I^AI^B.
Answer:
can you make this q more clear it doesnt rlly make sense
Explanation:
