One major reason for exploring extreme environments is to find new resources. An example of a resource is the search for a new antibiotic. Extreme environments have rare species endemic to the regions which can offer different insights from the normative environment we are used to.
No, I would not. This is because the risk of death is higher in an extreme environment. Example of these risks are deadly diseases or harsh climate. The body may be unable to adjust to the extreme environment hence may be unable to restore homoeostasis; such as in restoring body heat in extremely cold environments hence leading to hypothermia.
Oxygen Oxygen is the final electron acceptor, no part of the process - from the Krebs Cycle through the electron transport chain- can happen without oxygen. Aerobic respiration is complete
