Final answer:
An extreme halophile requires high salt concentration and cannot tolerate low salt. Obligate halophiles have specific salt requirements, while facultative halophiles can grow in a wide range of salt concentrations.
Step-by-step explanation:
An extreme halophile is an organism that can survive and thrive in extremely high salt concentrations. They require salt for growth and cannot tolerate low salt conditions. An example of an extreme halophile is Halobacterium, which can live in saturated brine solutions.
Obligate halophiles are similar to extreme halophiles but are more specific in their salt requirements. They require high salt concentrations and cannot grow in low salt conditions. They are unable to tolerate even slight decreases in salt concentration.
Facultative halophiles, on the other hand, can tolerate a wide range of salt concentrations but do not require high salt for growth. They can grow in low salt conditions but can also survive and grow in high salt conditions. An example of a facultative halophile is Staphylococcus aureus.