C. They unwinds the two strand of DNA.
Answer:
The question lacks options, the options are:
A. commensalism
B. mycorrhiza
C. parasitism
D. symbiosis
The answer is D, symbiosis (mutualism)
Explanation:
Organisms of same or different species interact with one another in their natural environment. The relationship between two organisms interacting with one another is called SYMBIOSIS. Symbiosis can be of different types depending on the effect of the relationship on the involved organisms. Symbiosis can be mutualistic, commensalistic or parasitic.
Mutualism is a kind of symbiosis in which the involved organisms benefit from the actions of one another. This is a case of the association between the root nodules of leguminous plant and rhizobium species.
Rhizobium is a bacteria genus found in the soil. They form nodules by attaching to the root of leguminous plants, which helps the plants to fix atmospheric nitrogen i.e converting gaseous nitrogen to a usable form (ammonia). In return, the plants provide organic acids for the Rhizobia bacteria, which they use as carbon and energy source. Hence, the association is a symbiotic relationship and specifically a mutualistic one.
The answer is no mycorrhiza because it is an association between a FUNGUS and a plant.
