Question

Annual rings are the number of
(1) Internodes in a stem
(2) Rings of vascular bundles in a monocot stem.
(3) Bark layers in a woody stem.
(4) Layers of Xylem in a stem.

Answer 1

Hint: The increment of wood added during a single growth period is represented by a growth ring in a cross-section of the stem of a woody plant. The growth period in temperate regions is usually one year, so the growth ring is referred to as an "annual ring". In tropical regions, growth rings may not be discernible or are not annual.

Complete answer:
Annual rings are the wood growth layers produced in the stems and roots of trees and shrubs each year. Wood cells produced when water is abundant and growth is rapid (generally corresponding to the spring or wet season) are often noticeably larger and have thinner walls than those produced when water is scarce and growth is slow (generally corresponding to the dry season).
As a result, there is a stark contrast between the small, thick-walled late-season wood cells produced one year and the large, thin-walled spring wood cells produced the next year. There is usually little or no gross visible contrast between the annual rings where the climate is uniform and growth is continuous, such as in wet, tropical forests, though differences do exist.
When the rings are visible, they can be counted to get a rough estimate of the tree's age. They also reflect the climatic and environmental factors that influence growth rates (due to their thickness range). The science of dendrochronology is founded on the phenomenon of annual ring thickness variability.
So, Annually, the tree produces new cells, which are organized in concentric circles known as annual rings or annual growth rings. These annual rings represent the amount of wood produced in a single growing season. The entire ring, known as the cambial ring, is formed as the stem grows. The Cambial Ring aids in the development of secondary xylem and secondary phloem.

So, the correct answer is “Option 4”.

Note:
Many trees grow one growth ring per year in areas with hot summers and cold winters. A year-by-year record or ring pattern is formed over the life of a tree, revealing the climate conditions in which the tree grew. When a tree grows in a dry environment, it is easier to determine its age than when it grows in a wet environment.