An organism that grows both in the presence and the absence of oxygen and uses oxygen when it is available is called a(n) .

Facultative anaerobe

Explanation:

Facultative anaerobes are the organisms that are able to grow both in oxygenic and anoxygenic environment but usually prefer oxygen to grow when it is present in the environment.  

Facultative anaerobes in absence of oxygen can switch to fermentation to form ATP and perform a metabolic function but they prefer aerobic respiration when oxygen is available. Bacteria living in our intestine are facultative anaerobes. The growth of these organisms is higher in aerobic conditions than anaerobic conditions.

Therefore the correct answer is a facultative anaerobe.

this protocol provides a detailed procedure for chromatin immunoprecipitation (chip) to study the dna-protein interactions.

the water is warmed up by the sun and then it evaporates into the atmosphere. the sunlight warms the water by its heat. water is then cooled down and condensation takes place. the water then finally returns back to the earth by the process of precipitation in the form of rain or ice.

explanation: