Which of the following best describes the nutritional modes of archaea (formerly known as archaebacteria)?

• A. Archaea can be either autotrophs or heterotrophs, depending on the species.
• B. All archaea are heterotrophs.
• C. All archaea are autotrophs.
• D. Archaea are exclusively photoautotrophs.

Answer: (A)

Verified step by step guidance

1. Understand the key nutritional modes in microbiology: autotrophs are organisms that produce their own food from inorganic substances (like CO2), while heterotrophs obtain their nutrients by consuming organic compounds.
2. Recall that archaea are a diverse group of microorganisms with varied metabolic capabilities, allowing them to survive in extreme environments.
3. Recognize that some archaea are autotrophs, capable of synthesizing organic molecules from inorganic sources, often through chemosynthesis rather than photosynthesis.
4. Acknowledge that other archaea are heterotrophs, relying on organic compounds for nutrition, similar to many bacteria and eukaryotes.
5. Conclude that the best description of archaea's nutritional modes is that they can be either autotrophs or heterotrophs, depending on the species.