Amoeba engulfs food particles by means of its

Analyze the question: It asks which structure Amoeba uses to engulf (capture and surround) food particles. This is about feeding, known as holozoic nutrition by phagocytosis.

Explain the concept: Amoeba is a single-celled organism with no fixed shape. It moves and feeds using pseudopodia ("false feet"), which are temporary extensions of its cytoplasm.

Step-by-step solution:

1. Amoeba detects a food particle, such as algae or bacteria.
2. It pushes out pseudopodia that flow around the particle.
3. The pseudopodia meet and fuse, trapping the particle in a pocket. This process is called phagocytosis.
4. The trapped particle is now enclosed in a food vacuole, where digestive enzymes break it down.
5. Digested nutrients diffuse into the cytoplasm, and undigested waste is egested at the cell surface.

Checking each option:

• A. Contractile vacuole: removes excess water (osmoregulation). Not for feeding.
• B. Cytoplasmic membrane: a boundary that controls what enters and leaves, but it doesn't actively surround food.
• C. Food vacuoles: these form after engulfing and are where digestion happens. They are the result of engulfing, not the means of it.
• D. Nucleus: controls cell activities and reproduction.
• E. Pseudopodia: the structures that actually surround and engulf the food. ✔

Tip: Link the words: pseudopodia = catch and engulf, food vacuole = digest, contractile vacuole = control water. In exams, ask whether the structure does the action in the question or is a product of it.