According to modern five kingdom classification, to which kingdom does the unicellular organism Amoeba belong?

Introduction / Context:
Amoeba is a well known single celled organism often studied in school laboratories and textbooks as an example of a simple eukaryote. Classification systems place organisms into kingdoms based on characteristics such as cell type, mode of nutrition, and level of organisation. This question asks you to recall which kingdom includes Amoeba in the widely used five kingdom system.

Given Data / Assumptions:

• Amoeba is unicellular and eukaryotic.
• Options include Plantae, Protista, Monera, Fungi, and Animalia.
• We assume the five kingdom classification (Monera, Protista, Fungi, Plantae, Animalia).
• We must choose the kingdom that best fits Amoeba's characteristics.

Concept / Approach:
In the five kingdom classification, Monera includes prokaryotes (bacteria), which lack a true nucleus. Amoeba, however, has a true nucleus and membrane bound organelles, so it is a eukaryote. Protista includes mostly unicellular eukaryotes such as Amoeba, Paramecium, and various algae. Fungi are multicellular (except for yeasts), have chitinous cell walls, and absorb nutrients, while plants (Plantae) are multicellular and photosynthetic. Animals (Animalia) are multicellular and ingest food. Amoeba is unicellular, heterotrophic, and moves using pseudopodia, fitting the kingdom Protista best.

Step-by-Step Solution:
Step 1: Identify Amoeba as a single celled organism with a nucleus and cytoplasmic organelles, making it eukaryotic. Step 2: Recall that Monera consists of prokaryotic organisms without a true nucleus, which excludes Amoeba. Step 3: Remember that Protista is the kingdom that includes mostly unicellular eukaryotes. Step 4: Observe that Plantae and Animalia primarily include multicellular organisms with specialised tissues. Step 5: Recognise that Fungi have cell walls of chitin and mostly grow as multicellular filaments, which does not match Amoeba. Step 6: Conclude that Amoeba belongs to kingdom Protista.

Verification / Alternative check:
Biology textbooks typically present Amoeba under kingdom Protista and use it as an example of a unicellular eukaryote. They describe its pseudopodia for movement and feeding, contractile vacuoles for osmoregulation, and nucleus, all of which are consistent with protist characteristics. Classification tables that compare Monera, Protista, Fungi, Plantae, and Animalia clearly place Amoeba with protozoan protists, not with bacteria, fungi, plants, or animals.

Why Other Options Are Wrong:
Plantae: Includes multicellular, photosynthetic organisms like trees and grasses; Amoeba is not photosynthetic. Monera (prokaryotic bacteria): Contains organisms without a true nucleus; Amoeba has a distinct nucleus. Fungi: Mostly multicellular decomposers with cell walls of chitin; Amoeba lacks this structure and lifestyle. Animalia: Contains multicellular animals with differentiated tissues; Amoeba is unicellular and does not fit.

Common Pitfalls:
Some students mistakenly associate Amoeba with animals because it moves and feeds on other organisms, or with Monera because it is unicellular. To avoid this, focus on the presence of a true nucleus and membrane bound organelles; these eukaryotic features place Amoeba firmly in Protista, not in Monera or Animalia.

Final Answer:
Amoeba belongs to the kingdom Protista.