Answer:
I didn't mean please tell me in simple
The correct answer for this question would be A.Live
1. A predicative nominative is a noun or a pronoun which follows a linking verb and refers to something before that verb. In your case, the correct answer is B, because "a shelter" goes after the linking verb "is", and refers to "a lean-to".
2. A participle has the form of infinitive + ing. In this case, the answer is D, flourishing.