OCR General Certificate of Secondary Education (GCSE) Biology Practice Exam

What is primarily increased by using rooting powder on plant cuttings?

1. The size of the leaves

2. The speed of root growth

3. The number of flowers

4. The overall height of the plant

The correct answer is: The speed of root growth

Using rooting powder on plant cuttings primarily increases the speed of root growth. This is because rooting powders typically contain plant hormones, such as auxins, which stimulate the development of roots in cuttings. These hormones encourage cellular differentiation and elongation, allowing the cuttings to establish a robust root system more rapidly than they would without the powder. The other options relate to aspects of plant growth that are not directly influenced by rooting powder. For example, while the size of the leaves and the overall height of the plant can be impacted by various factors such as light, water, and nutrients, they are not the primary focus of rooting powder. Additionally, the number of flowers is generally associated with the maturity of the plant and the conditions under which it is grown rather than the rooting process itself. Thus, the correct answer emphasizes the primary function of rooting powder in promoting the fast establishment of roots, which is essential for overall plant health and growth.