Which of the following groups is composed entirely of unicellular organisms?

• A. Bacteria
• B. Fungi
• C. Plants
• D. Animals

Answer: (A)

Verified step by step guidance

1. Step 1: Understand the concept of unicellular organisms. Unicellular organisms are composed of a single cell that performs all the necessary functions for life, such as metabolism, reproduction, and response to the environment.
2. Step 2: Review the characteristics of the groups listed in the problem: Bacteria, Fungi, Plants, and Animals. Determine which groups are known to include unicellular organisms.
3. Step 3: Analyze the group 'Bacteria.' Bacteria are prokaryotic organisms, and all members of this group are unicellular. They lack a nucleus and membrane-bound organelles.
4. Step 4: Examine the group 'Fungi.' Fungi include both unicellular organisms (like yeast) and multicellular organisms (like molds and mushrooms). Therefore, this group is not composed entirely of unicellular organisms.
5. Step 5: Evaluate the groups 'Plants' and 'Animals.' Both plants and animals are primarily multicellular organisms, with specialized cells forming tissues and organs. These groups do not consist entirely of unicellular organisms.