Which domain(s) include unicellular organisms?

• A. Bacteria
• B. Eukarya
• C. Archaea
• D. None of the above

Answer: (C)

Verified step by step guidance

1. Understand the concept of biological domains: In biology, all life forms are categorized into three domains: Bacteria, Archaea, and Eukarya. Each domain represents a major category of life with distinct characteristics.
2. Identify the characteristics of the domain Bacteria: Bacteria are unicellular organisms that lack a nucleus and other membrane-bound organelles. They are prokaryotic and can be found in various environments.
3. Identify the characteristics of the domain Archaea: Like bacteria, archaea are unicellular and prokaryotic. They often thrive in extreme environments, such as hot springs and salt lakes, and have unique biochemical properties.
4. Identify the characteristics of the domain Eukarya: Eukarya includes organisms with cells that have a nucleus and membrane-bound organelles. This domain includes both unicellular organisms, like protists, and multicellular organisms, such as plants and animals.
5. Conclude which domains include unicellular organisms: Both Bacteria and Archaea are entirely composed of unicellular organisms. Eukarya includes unicellular organisms as well, making all three domains inclusive of unicellular life forms.