B. photosynthesis is the major source of oxygen.
Answer:
An Oc mutation on the bacterial chromosome can affect the expression of structural genes on a F plasmid.
Explanation:
An Oc mutation is a mutation in which operator of an operon is constitutively active i.e. repressor fails to bind the operator which leads to unregulated gene expression.
An Oc mutation do not affect the expression of structural genes on F plasmid because <u>an operator is a cis regulatory element and therefore it can only affect the genes which are located on the same DNA</u>. F plasmid genes are located on the plasmid not on the main chromosome of the prokaryotes while tryptophan or lac operon system is in the main chromosome that is why an Oc mutation will not impact genes on plasmid.
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D, the light microscope !
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