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

What do you call organisms that are complex and larger, typically having a nucleus?

1. Prokaryotic organisms

2. Vertebrates

3. Eukaryotic organisms

4. Invertebrates

The correct answer is: Eukaryotic organisms

Eukaryotic organisms are defined by their complex cellular structures that contain a nucleus, where the genetic material is housed. This characteristic differentiates them from prokaryotic organisms, which lack a nucleus and are generally simpler and smaller in structure. Eukaryotes encompass a wide range of life forms, including plants, animals, fungi, and protists, and they can be unicellular or multicellular. The presence of organelles, such as mitochondria and endoplasmic reticulum, further enhances their complexity and allows for compartmentalization of cellular processes. While vertebrates and invertebrates refer to specific classifications of animals, they both fall under the broader category of eukaryotic organisms. Thus, the correct identification of eukaryotic organisms as those that are more complex and larger, typically featuring a nucleus, aligns perfectly with their biological classification.