<span>The ischemic penumbra can maintain metabolic demand with marginal blood flow from collateral circulation for a maximum of 50% before increasing in size. A penumbra is the area where the flow of blood at about 25 - 50% can maintain normal metabolic demands for 6 - 8 hours only. When it continues to increase, the human cells will die and other neurological activity will be suspended causing the person to die slowly.</span>
Termites depend on digestive tract to digest the complex sugars into simpler molecules that they can use for food. Cellulose is a major sugar and it is broken down in the hindgut of the termite by microbes into molecules called short-chain fatty acids. The termite's cells use these acids as nourishment, just like our cells do.
therefore, answer is A. mutualism
awnser is high concentrations of oxygen
