Chapter 19, Problem 16A

Summary Introduction

Introduction :

Any trace, impression, or preserved remains of an organism that have lived once in the past, is known as the fossil. Examples of fossils include DNA remnants, coal, oil, hair, or exoskeleton. Fossils are useful in studying the evolutionary process that has occurred over time and also the evolutionary relatedness among organisms.

Answer to Problem 16A

Correct answer :

The correct answer is option (C) foraminifera.

Explanation of Solution

Explanation/justification for the correct answer :

Option (C) foraminifera. Foraminifera is a type of amoeba that possesses test. The test is a hard and porous covering that surrounds the cell membrane of the organism. Organisms possessing tests generally live in the marine environment. Some may also be found in a freshwater environment. The test is responsible for protecting the organisms from the outside environment and the pores present in it allow the organism to extend its cytoplasm for activities

like locomotion. Test usually get fossilized that help geologists to study different rocks. So, the correct answer is option (C).

Explanation for incorrect answer :

Option (A) apicomplexans. Apicomplexans are also known as sporozoans and are characterized by the formation of spores for reproduction during their life cycle. These organisms do not have any such structure that usually gets fossilized. So, this is an incorrect option.

Option (B) flagellate. Flagellates are the organisms that possess flagella. The flagellum is a long whip or thread-like structure that is generally seen in plant-like protists. Flagella are generally present in one or two in numbers and help in the movement of the organism. It also acts as a sensory structure to sense the changes in the surrounding environment. These organisms do not have any such structure that usually gets fossilized. So, this is an incorrect answer.

Option (D) paramecia. Paramecium is a type of protozoa that possess cilia all over its body. Cilia are tiny hair structure present on the body of a paramecium. It is generally present in many numbers and help in locomotion and in capturing and internalizing the prey. These organisms do not have any such structure that usually gets fossilized. So, this is an incorrect answer.