Questions

‘Were’ needs to be replaced with ‘was’ to make the sentence grammatically correct. This is because, ‘If the subjects are joined by as well as, with, along with, together with, and not, in addition to, but, besides, except, rather than, accompanied by, like, unlike, no less than, nothing but, led by, headed by, guided by, controlled by,governed by,etc.. Then the verb will agree with the first subject. Thus, the correct formation would be, ‘The teacher as well as his wife was invited’.

Since, the starting statement carries a subject; R will be the first statement. The next statement describes why are they hunted, so Q follows P, as it states that what is being done with the horns. S would be the concluding statement and thus form a coherent paragraph.

The correct formation would be, ‘The Rhinoceros is hunted by poachers for its horn which is sold at high prices.’

‘One of the assistant’ needs to be replaced with ‘one of the assistants’ to make the sentence grammatically and contextually correct. This is because, ‘One of’ is always followed by a plural noun.