Rose and champa are two flowering plants that can reproduce through stem cutting. Stem cutting is a common method of plant propagation in which a section of the stem is cut and used to grow a new plant. This method is widely used because it is relatively simple and produces reliable results.

Stem cutting involves taking a healthy stem from a parent plant and cutting it into smaller sections. These sections are then planted in a suitable growing medium, such as soil or a rooting hormone, to encourage root development. Over time, the cuttings develop roots and grow into new, independent plants.

Stem cutting is an effective method of reproduction for many plants, including roses and champa. Here are the reasons why stem cutting is the correct answer:

1. Genetic similarity: Stem cutting allows for the production of genetically identical plants to the parent plant. This is because the cuttings are taken from the parent plant and retain the same genetic material. This is important for maintaining desirable traits in the new plants, such as flower color or growth habit.

2. Rapid growth: Stem cuttings generally root quickly and establish themselves as new plants faster than other methods of propagation. This is because the cuttings already have a portion of stem tissue that is capable of root development. With proper care and suitable growing conditions, the cuttings can begin to grow and develop into new plants within a few weeks.

3. Cost-effective: Stem cutting is a cost-effective method of plant propagation. It does not require expensive equipment or specialized techniques. Instead, it relies on basic gardening tools and materials that are readily available. This makes it accessible to home gardeners and commercial growers alike.

4. Versatility: Stem cutting can be used to propagate a wide range of plants, including flowering plants like roses and champa. This method is not limited to specific plant species or varieties, making it a versatile option for propagating different types of plants.

In conclusion, stem cutting is the correct answer because it is a simple, reliable, and cost-effective method of reproducing plants like roses and champa. It allows for the production of genetically identical plants and promotes rapid growth and establishment.