Irregular or variable shape

Amoeba is the correct answer as it has an irregular or variable shape. Let's further understand why amoeba has an irregular shape.

Explanation

Amoeba is a unicellular organism belonging to the kingdom Protista. It is a microscopic organism that can be found in freshwater bodies such as ponds and lakes. Amoebas are known for their ability to change their shape constantly and have an irregular or variable shape. This is due to the absence of a fixed cell wall or a rigid skeleton.

Morphological features of Amoeba

Amoeba has a simple structure with the following morphological features:

1. Shape: Amoeba appears irregular in shape and does not have a fixed body form. It can change its shape by extending finger-like projections called pseudopodia.

2. Pseudopodia: Pseudopodia are temporary projections of the cytoplasm that help in locomotion and capturing food. Amoeba extends pseudopodia in various directions, allowing it to move and engulf its prey.

3. Cytoplasm: The cytoplasm of amoeba is granular and contains various organelles such as nucleus, food vacuoles, and contractile vacuoles.

4. Nucleus: Amoeba has a single nucleus that controls the cellular activities.

5. Contractile vacuole: It helps in maintaining the water balance of the cell by expelling excess water from the cytoplasm.

Importance of irregular shape

The irregular shape of amoeba is essential for its survival and functioning. Here are a few reasons why the irregular shape is beneficial for amoeba:

1. Locomotion: Amoeba uses its pseudopodia to move in search of food or to escape from unfavorable conditions. The irregular shape allows it to change direction easily and navigate through its environment.

2. Feeding: Amoeba captures its prey by extending pseudopodia around it and forming a food vacuole. The irregular shape helps in engulfing and trapping the food efficiently.

3. Surface area to volume ratio: The irregular shape increases the surface area to volume ratio of amoeba, allowing for efficient exchange of gases and nutrients with the environment.

4. Adaptability: The irregular shape of amoeba allows it to adapt to various environmental conditions. It can change its shape to squeeze through narrow spaces or to avoid predators.

In conclusion, amoeba has an irregular or variable shape due to the absence of a fixed cell wall or skeleton. This shape enables amoeba to perform various functions such as locomotion, feeding, and adaptability, making it a successful and versatile organism.

Amoeba is a unicellular organism which has an irregular or variable shape.