2. which of the following can survive either with oxygen or without it?
obligate aerobes
obligate anaerobes
facultative anaerobes
bacteriophages
3. where are you likely to find a photoautotroph?
in your refrigerator
in the deepest parts of the ocean
in your digestive system
near the surfaces of lakes and streams
4. during what process do prokaryotes exchange genetic information?
cell division
binary fission
conjugation
endospore formation
5. what would be a direct consequence of the disappearance of nitrogen-fixing prokaryotes?

2.The answer is; facultative anaerobes. Facultative means optionally while obligate means obligatory. Therefore obligate anaerobes only thrive in the presence of oxygen while obligate anaerobes thrive in the absence of oxygen. Examples of facultative anaerobes are Staphylococci and Escherichia bacterias

3.The answer is; near the surfaces of lakes and streams. Photoautotrophs are organisms that synthesize biomolecules and harness their energy from light. They use the process of photosynthesis to capture the light photons. The organism will be found on the surface of lakes and stream where sunlight can reach and to depths that light can penetrate.

4.The answer is; conjugation.  In bacteria, this process occurs through a structure called pili that forms in the ‘male’ bacteria. It is through the exchange of the genetic material that bacteria confer traits such as drug resistance to other bacteria. It’s a horizontal method of gene transfer.

5.The answer is; Organisms would not be able to get nutrients they need to make proteins. Nitrogen-fixing bacteria fix nitrogen in the soil. This means that they convert the abiotic form of nitrogen from the atmosphere to organic molecules such as ammonia. Ammonia is absorbed by organisms such as plants and becomes a constituent of amino acids that make up proteins.

during the process of dna replication, brdu can replace thymidine and incorporate into the newly synthesized dna, cell proliferation thus can be reflected in the extent of brdu incorporation.