Final answer:
Anaerobic organisms require reduced oxygen conditions for growth, as they are obligate anaerobes that can be killed by the presence of oxygen, necessitating the use of special culture methods like an anaerobic jar.
Step-by-step explanation:
To grow on laboratory media, anaerobic organisms require reduced oxygen conditions, specifically an environment that lacks oxygen. These organisms are termed obligate anaerobes and they use fermentation or anaerobic respiration to generate energy.
Obligate anaerobes, such as those grown in tube B mentioned in the background information provided, are killed by oxygen. Therefore, they must be cultured in equipment like an anaerobic jar to ensure the absence of oxygen. Other types of bacteria that vary in their oxygen needs include facultative anaerobes, which can grow with or without oxygen, aerotolerant anaerobes that do not require oxygen but are not harmed by it, and microaerophiles, which require lower levels of oxygen than are present in the atmosphere.
To conclude, the specific requirements of anaerobic organisms dictate that their laboratory cultures must be carefully managed to exclude oxygen to support their growth.