Practice Test: Reading Comprehension - 18 | 100 RCs for GMAT PDF Download

Directions: Read the given passage carefully and answer the questions as follows:

Antibiotics are chemical substances that kill or inhibit the growth of bacteria. The success of antibiotics against disease-causing bacteria is one of modern medicine’s great achievements. However, many bacteria harmful to humans have developed ways to circumvent the effects of antibiotics, and many infectious diseases are now much more difficult to treat than they were just a few decades ago. Antibiotic resistance is an especially difficult problem for hospitals with critically ill patients who are less able to fight off infections without the help of antibiotics.
Bacteria can develop antibiotic resistance because they have the ability to adapt quickly to new environmental conditions. Most commonly, bacteria share with each other genetic material called resistance plasmids; these shared plasmids, which contain the genetic code enabling antibiotic resistance, can spread throughout a bacterial population to create a strain of resistant bacteria. Less commonly, a natural mutation that enables antibiotic resistance takes place within the chromosome of the bacteria, and the resulting strain of bacteria can reproduce and become dominant via natural selection. In the absence of human involvement, however, bacteria in the wild rarely develop resistance to antibiotics.
In the United States, animals raised on industrial-scale factory farms are routinely administered low levels of antibiotics in their feed not as a cure for ongoing maladies, but primarily as a growth-enhancing agent to produce more meat and also as a prophylactic measure to compensate for overcrowded and unsanitary conditions.
Currently, several antibiotics that are used in human medical treatment are administered non-therapeutically to healthy livestock and poultry. Examples include tetracycline, penicillin and erythromycin. This long-term non-therapeutic feeding of antibiotics to animals creates the ideal conditions for the development of antibioticresistant bacteria, as it kills the susceptible bacteria while leaving the resistant strains to reproduce and flourish.
Europe is far ahead of the United States in the responsible use of antibiotics: On January 1, 2006, the European Union banned the feeding of all antibiotics to livestock for nontherapeutic purposes. This sweeping policy follows a 1998 ban on the non-therapeutic use of four medically-important antibiotics on animals. The time has come for the United States to follow Europe’s lead.