Concept:The Amoeba is a unicellular organism that changes its shape continuously with the help of temporary projections called pseudopodia.
Explanation:The Amoeba alters its body shape by extending and retracting pseudopodia.
Pseudopodia are temporary cytoplasmic projections used for movement and capturing food.
This shape-changing ability enables the Amoeba to adapt to different surroundings, such as water and soil.
In contrast, the other cell types possess fixed shapes.
Smooth muscle cells are spindle-shaped and line the walls of internal organs like the intestines and blood vessels.
The ovum is the female reproductive cell with a fixed spherical shape.
Nerve cells have long extensions called axons and dendrites, giving them a stable structure needed for transmitting nerve impulses.
Answer:Amoeba (Option C)