The stomatal openings of plants 6-8 are smaller than those of the other plants; those of plants 9 and 10 are intermediate in size.
Plants 6-8 are experiencing drought stress and have closed their stomata; plants 9 and 10 are starting to close their stomata.
The statement indicates that the stomatal openings (small pores on the surface of leaves and stems that regulate gas exchange) of plants 6-8 are smaller than those of the other plants, while the stomatal openings of plants 9 and 10 are intermediate in size.
Stomatal size can be influenced by various factors, including environmental conditions, genetics, and plant physiology.