Which statement concerning grafting is correct? stocks and scions refer to twigs of different species. stocks provide root systems for grafting. grafting creates new species. stocks and scions must come from unrelated species.

Stocks provide root systems for grafting

Explanation:

When the tissues of plants are joined together to let them continue their growth together as one, then such a practice is known as grafting.Grafting is commonly practiced in horticulture and agriculture for the growth of commercially important plants in an asexual manner.In the process of grafting, the upper part of the combined plant is known as scion and the lower part is known as the stock. The stock is selected for its root system whereas the scion is selected for its flowers, leaves or stem. The success of the graft depends on the joining of the vascular tissues of the stock and scion so that the plant grows together as one.

The answer is ozone layer.