Which of the following structures is only formed during cell division in animal cells?

Step 1: Analyze the question We need the structure that is only formed during cell division in animal cells. In other words, it is not a permanent feature of the cell at all times.

Step 2: Explain the concepts

• Cell membrane: present in every cell all the time.
• Cytoplasm: present in every cell all the time.
• Ribosome: present permanently, since it is needed for protein synthesis.
• Centrosome / centrioles: In animal cells, the centrioles duplicate before division. During cell division (prophase), the centrosomes move to opposite poles and organize the spindle fibres (the spindle apparatus), which separate the chromosomes. Of the options listed, the centrosome is the one associated specifically with cell division in animal cells, since plant cells lack centrioles.

Step 3: Eliminate the options

• A: Cell membrane is always present, so it is not formed only during division.
• B: Cytoplasm is always present, so this is wrong.
• D: Ribosomes are always present, so this is wrong.
• C: Centrosome is the structure that becomes active and organizes the spindle during division, so it is the best answer.

A note on accuracy: Strictly speaking, a centrosome is present in the cell during interphase too (it is duplicated in S phase), and it is the spindle it organizes that forms only during division. For the exam, choose C.

Step 4: Answer The correct option is C. Centrosome.

Exam tip: Remember "Centrosome = Cell division in animals." Plant cells divide without centrioles, so centrioles and spindle formation are key animal-cell division features.