Q.These questions consist of two statements each printed as Assertion and Reason. While answering these questions you are required to choose any one of the following four responses.
A. If both Assertion and Reason are true but the Reason is a correct explanation of the Assertion.
B. If both Assertion and Reason are true but Reason is not a correct explanation of the Assertion
C. If Assertion is true but the Reason is false.
D. If both Assertion and Reason are false.

1. Assertion: In woody stems the amount of heart wood continue to increase year after Year
   Reason: The activity of cambial ring continues uninterrupted
   a. A
   b. B
   c. C
   d. D
2. Assertion: Secondary growth in dicot roots occurs with the help of vascular cambium and phellogen.
   Reason: Vascular cambium is completely primary in origin.
   a. A
   b. B
   c. C
   d. D

Step 1. Evaluate Assertion 1. 'In woody stems the amount of heart wood continues to increase year after year' is TRUE - as a tree ages, more of its sapwood is progressively converted into heartwood (vessels blocked by tyloses, infiltrated with tannins/resins), so the proportion of heartwood grows steadily over the tree's lifetime.

Step 2. Evaluate Reason 1. 'The activity of cambial ring continues uninterrupted' is TRUE in the relevant sense - the vascular cambium keeps functioning season after season throughout the tree's life (even though its rate of activity varies seasonally, producing spring wood and autumn wood, it does not permanently stop), continually laying down new secondary xylem.

Step 3. Check whether Reason 1 correctly explains Assertion 1. Yes - it is precisely because the cambium keeps adding new xylem year after year that older, inner xylem layers keep being converted to heartwood, so the amount of heartwood keeps increasing. The Reason is a correct explanation of the Assertion, matching option A.

Step 4. Evaluate Assertion 2. 'Secondary growth in dicot roots occurs with the help of vascular cambium and phellogen' is TRUE - as covered earlier in the chapter, root secondary growth involves exactly these two lateral meristems, just as in the stem. …

Evaluate each Assertion and Reason against the chapter's own facts about cambial activity and root cambium origin, then m …

• Assuming 'continues uninterrupted' must be false because cambial activity varies seasonally, rather than reading it as 'never permanently stops' across the tree's life. …