Chapter 25, Problem 1TYK

Choose the best definition of a fossil.

a. any trace of an organism that has been converted into rock

b. a bone, tooth, shell, or other hard part of an organism that has been preserved

c. any trace of an organism that lived in the past

d. any part of a dead organism

Summary Introduction

Introduction:

The shells, bones, teeth, hair, exoskeletons, or stone imprints are included in the fossils. They are studied for their age, formation process, and significance in evolution. The study of the fossil is called paleontology and the totality of fossil is termed as fossil records.

Answer to Problem 1TYK

Correct answer:

The fossil is any trace of an organism that lived in the past. The preserved remains or traces of any part or whole of an organism that was once living, are called fossils.

Explanation of Solution

Explanation/Justification for the correct answer:

Option (c) is given as any organism traces that lived in the past. The fossil can be explained as the remains or traces of an organism, which was once living. The fossils are the physical proof or evidence that gives information about the organisms that once lived in the past. Hence, option (c) is correct.

Explanation for incorrect answers:

Option (a) is given as any organism’s traces that are converted into rocks. These are formed when a part or the whole organism gets buried under a lot of pressure in the sand, mud, or ash. The course of time causes mineralization of the organism, which then turns into fossils. So, it is an incorrect option.

Option (b) is given as any hard parts that have been preserved. Soft parts of the organisms that are preserved can also be considered as fossilized remains. So, it is an incorrect option.

Option (d) is given as any part of a dead organism. It is not necessary that only a dead organism that has been preserved may be described as a fossil. So, it is an incorrect option.

Hence, options (a), (b), and (d) are incorrect.

Conclusion

The hard traces or remains of an organism that had once lived in the past, like bones, teeth, and shells get converted into rocks. The soft traces like hair are also preserved but not in the form of a rock. Thus, the fossil is any part of the dead organism that has been preserved, and which serves as a trace to study that organism.