Anatomy Of Flowering Plants Question 34
Question: Annual rings are the bands of:
Options:
A) secondary cortex and cork
B) all secondary vascular tissues
C) secondary xylem and xylem rays
D) secondary phloem and medullary rays
Show Answer
Answer:
Correct Answer: C
Solution:
- Outside the cambium. The outer cells become part of the phloem.
The phloem carries food produced in the leaves to the branches, trunk, and roots. Some of the phloem dies each year and becomes part of the outer bark.
- Inside the cambium. The inner cells become part of the xylem.
These cells contribute most of a tree’s growth in diameter. The xylem carries water and nutrients from the roots to the leaves. These cells show the most annual variation. When a tree grows quickly, the xylem cells are large with thin walls.
This early wood or springwood is the lighter-colored part of a tree ring. In late summer, growth slows; the walls of the xylem cells are thicker. This late wood or summerwood is the darker-colored part of a tree ring.
So, annual rings are bands of secondary xylem and xylem rays.
Therefore, the correct answer is option C.
BETA
