(k ) The development of antibiotic-resistant strains of bacteria necessitates the development of new antibiotics
(l ) People can be immunised against a disease by introducing small quantities of dead or inactive forms of the pathogen into the body (vaccination). Vaccines stimulate the white blood cells to produce antibodies that destroy the pathogens. This makes the person immune to future infections by the microorganism. The body can respond by rapidly making the correct antibody, in the same way as if the person had previously had the disease. MMR vaccine is used to protect children against measles, mumps and rubella.
(m ) Uncontaminated cultures of microorganisms are required for investigating the action of disinfectants and antibiotics.
(n ) In school and college laboratories, cultures should be incubated at a maximum temperature of 25 °C, which greatly reduces the likelihood of growth of pathogens that might be harmful to humans
(o ) In industrial conditions higher temperatures can produce more rapid growth.
