Massachusetts Comprehensive Assessment System (MCAS) Biology Practice Test

The process responsible for generating new root cells in plants as they grow is mitosis. Mitosis is the type of cell division that results in two genetically identical daughter cells, allowing for growth and development. In the roots of plants, active meristematic tissues, particularly in the root tips, continuously divide through mitosis to produce new root cells. This division is essential for plants to increase their root mass and develop a more extensive root system, which is crucial for anchoring and nutrient uptake.

Cell differentiation is a subsequent process where the newly formed cells take on specialized functions but does not itself generate new cells. Meiosis, on the other hand, is involved in producing gametes for sexual reproduction and does not contribute to root growth. Photosynthesis is the process through which plants convert sunlight into energy but does not directly create new plant cells. Thus, the correct answer highlights the fundamental role of mitosis in plant growth and root development.