Which term corresponds to 'Simplest single-celled organisms, often colonial'?

Which term corresponds to 'Simplest single-celled organisms, often colonial'?

• A. Bacteria
• B. Protozoa
• C. Helpful Bacteria
• D. Harmful Bacteria

Answer: (A)

Bacteria are the simplest single-celled organisms and commonly form colonies. They’re prokaryotic, meaning they lack a nucleus and have a straightforward internal structure, which fits the description of the “simplest” single-celled life. Protozoa are also single-celled but are eukaryotic and more complex, so they don’t fit as the simplest term. The other options describe the bacteria’s role (helpful or harmful) rather than the basic organism type, so they aren’t the correct general term.

Bacteria are the simplest single-celled organisms and commonly form colonies. They’re prokaryotic, meaning they lack a nucleus and have a straightforward internal structure, which fits the description of the “simplest” single-celled life. Protozoa are also single-celled but are eukaryotic and more complex, so they don’t fit as the simplest term. The other options describe the bacteria’s role (helpful or harmful) rather than the basic organism type, so they aren’t the correct general term.