Chapter 19, Problem 14A

Summary Introduction

Introduction :

Paramecium is a type of protozoa. Protozoa are animal-like protists that follow a heterotrophic mode of nutrition and are thus characterized as heterotrophs. Protozoans generally ingest other protozoans, algae, and bacteria to obtain energy and nutrition.

Answer to Problem 14A

Correct answer :

The correct answer is option (A) cilia.

Explanation of Solution

Explanation/justification for the correct answer :

Option (A) cilia. Cilia are tiny hair structure present on the body of a paramecium. It is generally present in many numbers and in paramecium, these structures cover the whole body of the organism. Cilia help in locomotion and in capturing and internalizing the prey. So, the correct answer is option (A).

Explanation for incorrect answer :

Option (B) contractile vacuole. The contractile vacuole is specifically helpful for aquatic organisms in maintaining homeostasis or water balance in their body. The vacuole collects the excess water present in the body of the organism (generally unicellular) or the cytoplasm and then expels it outside the body or cell. The vacuole may also contain some waste products that also get expelled out along with water. Paramecium has two contractile vacuoles. So, this is an incorrect option.

Option (C) 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. Flagella are not present in paramecium. So, this is an incorrect answer.

Option (D) pseudopodia. Pseudopod is a cytoplasmic extension and is a temporary structure formed in protozoans. This structure is generally used for motility and capturing food by organisms belonging to class Sarcodina of protozoa. Pseudopodia are not present in paramecium. So, this is an incorrect answer.