Biology STAAR (State of Texas Assessments of Academic Readiness) Practice Test

Which of the following best describes protozoa?

1. They are classified based on their color

2. They are found only in freshwater environments

3. They move using flagella, pseudopods, or are non-motile

4. They primarily reproduce through binary fission

The correct answer is: They move using flagella, pseudopods, or are non-motile

Protozoa are a diverse group of single-celled organisms that can exhibit a variety of movement methods, which include the use of flagella (tail-like structures), pseudopodia (temporary arm-like projections), or being non-motile (not moving). This characteristic of locomotion is significant as it helps define how different protozoan species interact with their environment and capture food. While some protozoa are indeed capable of moving in one of these ways, they do not all share the same mode of movement. For instance, paramecia use cilia for movement, while amoebas extend pseudopodia to travel or engulf food. Other options delve into characteristics that do not comprehensively describe protozoa. Classifying them solely based on color does not accurately reflect their biological diversity and ecological roles. Suggesting they are found only in freshwater environments excludes many species that inhabit marine or terrestrial ecosystems. The assertion that protozoa primarily reproduce through binary fission overlooks the presence of other reproductive strategies, such as sexual reproduction or multiple fission. Thus, the description emphasizing movement through flagella, pseudopodia, or being non-motile accurately captures a fundamental aspect of protozoan biology.