Question

Because scientists have studied fossils, they know a great deal about the geological history of Earth. From fossils, scientists have learned

that many changes have taken place on Earth. For example, they know vegetation once grew in Earth's cold, Bless polar regions and now it does
not. Also, because of fossil research scientists know that dinosaurs once roamed Earth
Which sentence, if added to the passage, would best help the reader understand the meaning of the word "fossils"?
01. Geologists are scientists who study fossils and other structures of Earth
2. Fossils are a part of our past one of the few things unchanged by human progress
03 Fossils are the hardened remains of plant or animal life from a previous geologic age.
Historians and geologists are also finding the information gained from the study of fossils to be useful

Answer 1

The sentence that, if added to the passage, would best help the reader understand the meaning of the word "fossils" is:

3. Fossils are the hardened remains of plant or animal life from a previous geologic age.

Step-by-step explanation:

When an author introduces a word in his writing that he believes the audience may not know, he can choose to include context clues to help the audience grasp its meaning.

One type of context clue offers a definition of the word's meaning. That is the case with option 3. It provides the audience with a dictionary-like meaning of the word "fossils", helping them understand not only the word itself, but also the whole passage.

The other options, even if not detached from the general idea of the passage, do not necessarily help the audience understand the meaning of "fossils". If the reader does not know the word's meaning already, adding any of these options will not at all help him grasp it.