Which of the following is common to mitosis and meiosis?
a. Spindle
b. Crossing over
c. Tetrad of chromatids
d. Cytokinesis

Verified step by step guidance

1. Step 1: Understand the processes of mitosis and meiosis. Both are types of cell division but serve different purposes: mitosis results in two identical daughter cells, while meiosis produces four genetically diverse gametes.
2. Step 2: Review the options given: (a) spindle, (b) crossing over, (c) tetrad of chromatids, and (d) cytokinesis. Identify which features occur in both mitosis and meiosis.
3. Step 3: Recall that the spindle apparatus is a structure made of microtubules that helps separate chromosomes during cell division. It forms in both mitosis and meiosis.
4. Step 4: Recognize that crossing over (exchange of genetic material between homologous chromosomes) and tetrads (paired homologous chromosomes) are specific to meiosis, not mitosis.
5. Step 5: Cytokinesis, the division of the cytoplasm, occurs in both mitosis and meiosis, but since the question asks for what is common, consider which option best fits both processes.

Key Concepts

Spindle Apparatus

The spindle apparatus is a structure composed of microtubules that forms during cell division. It is responsible for separating chromosomes into daughter cells in both mitosis and meiosis, ensuring accurate distribution of genetic material.

Crossing Over

Crossing over is the exchange of genetic material between homologous chromosomes during prophase I of meiosis. This process increases genetic diversity and does not occur in mitosis.

Cytokinesis

Cytokinesis is the division of the cytoplasm following nuclear division, resulting in two separate daughter cells. It occurs at the end of both mitosis and meiosis, completing the cell division process.