Michigan Test for Teacher Certification (MTTC) Secondary Integrated Science Practice test

Which tissues provide structural support in the stems of plants?

1. Parenchyma and collenchyma

2. Sclerenchyma and collenchyma

3. Xylem and phloem

4. Fibers and endodermis

The correct answer is: Sclerenchyma and collenchyma

The correct choice highlights that sclerenchyma and collenchyma tissues are primarily responsible for providing structural support in the stems of plants. Sclerenchyma consists of thick-walled cells that are typically dead at maturity. They have a rigid structure due to the presence of lignin, a complex organic polymer that strengthens the cell walls and is key to supporting plant tissues. This tissue generally provides the necessary toughness and support needed to withstand mechanical stress, especially in woody plants. Collenchyma, on the other hand, consists of living cells that have thicker primary cell walls, allowing for flexibility while still providing support. It is commonly found in young stems and leaf petioles, giving them the ability to bend without breaking, which is crucial for plants that experience wind or other physical disturbances. The combination of these two types of supportive tissues allows plants to maintain their structure while still allowing for growth and flexibility, which is essential for their overall survival and adaptation in various environments.