Answer:
Multiple alleles can modify the classical Mendelian ratio by increasing the number of phenotypes.
For example, in a monohybrid cross, Mendel gets only 2 phenotypes however, in ABO blood groups (a classical example of multiple alleles) there are four phenotypes present in a population.
Lethal alleles are the alleles which when expressed result in the death of an organism. These alleles can be dominant, recessive or conditional (depends on interaction with another gene).
Thus, lethal allele reduces the ratio of the phenotype associated with it by affecting the survival of the organism.
For example, lethal yellow allele in mice results changes the phenotype ratio from 3:1 to 2:1
The nurse should explain that during surgery,
an antibiotic prophylaxis is administered to prevent the incidence of surgical
site infection. The use of antibiotic before the procedure is just
one of many actions taken to help reduce the rate of wound infections.
Furthermore, the initial dose must be given most likely within 30
minutes before incision. Then, the next dose is at one to two half-lives of the
antibiotic, which is recommended for the duration of the surgery. Thus,
appropriate timing of dose is essential to the effectiveness of the antibiotic.
Answer:
The humoral immune response involves mainly B cells and takes place in blood and lymph.
Explanation: