Concept:The correct sequence arranges the sentences so that the explanation moves logically: from general mutations, to most genes being harmless, then to the few cancer-causing oncogenes, their normal role, and finally the consequence of mutation.
Explanation:Sentence
S1 states mutations are random changes in base sequences.
Sentence
S6 says multiple mutations cause a tumour.
The first middle sentence must follow
S1 naturally.
R: "Most genes do not cause cancer if they mutate" continues the idea of random change — it clarifies that not all mutations lead to cancer.
Q: "The few genes that can become cancer‑causing after mutating are known as oncogenes" nicely contrasts with
R by introducing the special genes that do cause cancer.
S: "In a normal cell oncogenes are involved in the control of cell cycle and cell division" explains the normal function of those genes, setting up why their mutation is dangerous.
P: "This is why mutations in them can result in uncontrolled cell division and therefore tumour formation" directly links the normal role to the consequence described in
S6.
Thus the proper sequence is
R,
Q,
S,
P.
Answer:RQSP (Option A).