The diagram shows a cross-section of a plant root.
What is a function of the part labelled Q?
A) storage of starch
B) structural support
C) transport of amino acids
D) transport of glucose
▶️ Answer/Explanation
Ans: B
The part labelled Q is likely the root cortex or vascular tissue, which provides mechanical strength and structural support (B) to the plant.
Starch storage (A) occurs in specialized cells like amyloplasts, while amino acids (C) and glucose (D) are transported via phloem, not typically labelled as Q. Thus, the correct answer is B.
Which feature of xylem vessels provides support to plants?
A) cells are joined end to end
B) no cell contents
C) no cross-walls
D) lignin present
▶️ Answer/Explanation
Ans: D
Lignin is a rigid, waterproof polymer that strengthens the walls of xylem vessels, providing structural support to the plant.
Options A, B, and C describe features of xylem vessels (e.g., continuous tubes, absence of organelles, and no cross-walls), but these primarily aid in water transport, not support.
Since lignin deposition makes xylem vessels rigid and resistant to collapse, the correct answer is D (lignin present).