option d is the correct ans
Sentence three is the correct sentence. All of the others have some grammatical error in them. In the first, "felled" is incorrect and not a word. It also says "walk boots" instead of the correct verbal adjective "walking boots." In the second, "weren't" is not usually considered very academic and "tight" should be in the adverb form "tightly." Number four is wrong because it used "walked boots" instead of of "walking boots" and "tight" instead of "tightly." "Fallen" is incorrect in number 4, because it should have been "had fallen" if one was going to use the verb "fallen."
Answer:
Based from the definition of terms presented, the following is the answer to the questions.
1. B. The study of statistics such as birth rate and death rate.
2. B. A group of symptoms that occur together.
