The sequence of events you are describing pertains to prophase, which is the first stage of mitosis. During prophase, several key processes occur:
- Chromosomes become visible: The chromatin condenses into distinct chromosomes, which can be seen under a microscope.
- Nuclear envelope dissolves: The nuclear membrane breaks down, allowing the microtubules of the spindle apparatus to access the chromosomes.
- Spindle forms: The spindle apparatus, composed of microtubules, begins to form and will help separate the chromosomes during cell division.
The other terms you mentioned are related but distinct from prophase:
- Cell theory: A fundamental concept in biology that states all living organisms are composed of cells, cells are the basic unit of life, and all cells arise from pre-existing cells.
- S phase: The phase in the cell cycle where DNA replication occurs, resulting in the duplication of chromosomes before mitosis starts.
So, if you are looking for the correct answer among your options regarding the specific events that occur during the early stages of cell division, Prophase is the accurate term.