Answer:
67. Obligate anaerobes
68. Aerotolerant anaerobes
69. pH
70 media nutrient density
71. agar concentration
72. extremophiles
Explanation:
Anaerobes are microorganisms which do not require oxygen for their metabolic activities. The types of anaerobes based on metabolism are: obligate anaerobes; facultative anaerobes ; and aerotolerant anaerobes.
Some bacteria are anaerobes.
67. Obligate anaerobes do not require oxygen at all for their metabolism. They die in the presence of oxygen.
68. Aerotolerant anaerobes do not require oxygen as well but can also tolerate oxygen. they are unaffected by the presence or absence of oxygen
69. The pH of the medium affects the growth of bacteria. When pH becomes too low or too high, bacteria colonies begin to die.
70. when the nutrient concentration is high, growth rate of bacteria colony increases, but when it is low, bacteria colony growth decreases.
71. agar concentration limits the growth of bacteria colony. When the agar is very concentrated, that is the medium is hard, the bacteria colony is limited in their ability to move and vice versa.
72. Extremophiles is the name given to archaea that thrive in extreme conditions of temperature and pH. For example, the archaeal Methanopyrus kandleri strain 116 grows at 122 °C while the genus Picrophilus e.g., Picrophilus torridus has the ability to grow at a pH of 0.06.
