Which movable chitinous plate is joined with dorsal part of head :-
(a) Labrum
(b) Clypeus
(c) Labium
(d) Forehead or frons

Options

A. Labrum
B. Clypeus
C. Labium
D. Forhead or frons

Answer

To solve the question "Which movable chitinous plate is joined with the dorsal part of the head?" we need to analyze each of the given options:

1. **Understanding the Options:**
- (a) **Labrum**: This is known as the upper lip in insects and is indeed a chitinous structure that is movable. It is connected to the dorsal part of the head.
- (b) **Clypeus**: This is a sclerite that forms part of the face of arthropods but does not function as a movable plate connected to the dorsal part of the head.
- (c) **Labium**: This forms the lower lip of insects and is not associated with the dorsal part of the head.
- (d) **Forehead or Frons**: This also contributes to the face structure of insects but is not a movable chitinous plate connected to the dorsal part of the head.

2. **Identifying the Correct Answer:**
- Since the labrum is the only structure that is a movable chitinous plate and is connected to the dorsal part of the head, it is the correct answer.

3. **Final Answer:**
- The correct answer is (a) Labrum.