Retired professor of math and computer science having taught for 36 years at a state supported university in Virginia. United States Senators serve a term of six years in office. There is no limit on how many terms a Senator can be elected to serve.
Herbaceous perennials are garden plants that die back to the soil line when winter temperatures arrive. The plants enter a dormant period and strengthen the root system while waiting for the coming of spring.
The tubes in the stem that take the water and minerals up into the plant are the xylem and the tubes that carry the food back down are called the phloem. Stems can be of several sorts, herbaceous and woody. The herbaceous stems are green and fairly bendable. The woody stems as their name implies, are covered by bark. The herbaceous stem has more pith for its size. The cambium which causes woody stems to get bigger in width is not as active in the herbaceous stems.