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

What is the primary function of xylem in plants?

1. Transport of nutrients

2. Transport of water

3. Storage of food

4. Photosynthesis

The correct answer is: Transport of water

The primary function of xylem in plants is the transport of water. Xylem is a type of tissue that is specifically designed to carry water and dissolved minerals from the roots upwards through the plant to various parts, including the leaves, stems, and flowers. This movement of water is crucial for various physiological processes, such as photosynthesis, nutrient transport, and maintaining cell turgor, which helps keep the plant rigid and upright. In addition to water transport, xylem also provides structural support due to the presence of lignin, which strengthens the cell walls. However, the primary role remains centered around water movement. Other functions mentioned in the options, such as nutrient transport, food storage, and photosynthesis, are carried out by different tissues in plants. Nutrient transport primarily involves the phloem, while food storage can occur in various plant parts such as roots and seeds, and photosynthesis takes place mainly in the leaves through chlorophyll-containing cells. Therefore, the correct focus on the xylem as primarily responsible for water transport highlights its essential role in plant biology.