Women ages 30 through 65 can then be screened every 5 years with Pap and HPV cotesting or every 3 years with a Pap test alone. The guidelines also note that women with certain risk factors may need to have more frequent screening or to continue screening beyond age 65.
Petioles support leaf growth. Also called the leaf stalk, the petiole is actually an extension of the leaf in certain plants. It is the structure that connects the leaf to the stem or trunk of most vascular plants.
Detailed Description of the Experiment. Leaf stomata are the principal means of gas exchange in vascular plants. Stomata are small pores, typically on the undersides of leaves, that are opened or closed under the control of a pair of banana-shaped cells called guard cells (see figure above). When open, stomata allow CO2 to enter the leaf for synthesis of glucose, and also allow for water, H2O, and free oxygen, O2, to escape.