Answer: A) Remove the phrase “It is petrifying” because it expresses a personal feeling and D) Add the phrase “and spread throughout the human species” to the end of the statement to more fully express the central idea.
Explanation: When writing a summary of the central idea of a text, we have to express the ideas in a brief and clear way, without including personal opinions or irrelevant details. In the given paragraph from "The Hot Zone" we can see that the main idea is that viruses can "come alive" even after death, and spread throughout the human species, so to improve the given summary we should remove the phrase “It is petrifying” because it expresses a personal feeling (and it is not objective) and also add the phrase “and spread throughout the human species” to the end of the statement because it is an important part of the main idea.
