A commensal bacterium does not infect its host, which is option D. Details about commensalism can be found below.
<h3>What is commensalism?</h3>
Commensalism is a kind of relationship that involves the sharing of the same environment by two organisms where one species benefits and the other is unaffected.
For example, barnacles on whales is a commensalistic relationship.
According to this question, a commensal bacterium will not affect or harm it's host by infect it neither will it benefit its host.
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Mitoses and Asexual Reproduction by cell division,one cell divides to become two
External respiration (correct answer) involves the exchange of oxygen and carbon dioxide within the environment.
The exchange of wastes through the skin is just called excretion by sweating.
There is no exchange of nutrients that occur in the lungs but rather absorption of nutrients is the function of the gastrointestinal tract.
The exchange of oxygen and carbon dioxide within the cell is called cellular respiration and involves carrying oxygen from the blood to the cell then the cell uses it as the final electron acceptor in the electron transport chain. The metabolic wastes of the cell, primarily carbon dioxide, goes now to the bloodstream to be exchanged for oxygen in the lungs.
Gulls, crows and herons are all opportunists. They'll eat just about anything that they can get their beaks on. That includes fiddler crabs.
