Match List I with List II.
List I | List II | ||
A | Taenia | I | Nephridia |
B | Paramoecium | II | Contractile vacuole |
C | Periplaneta | III | Flame cells |
D | Pheretima | IV | Urecose gland |
Choose the correct answer from the options given below:
If the value of \( \cos \alpha \) is \( \frac{\sqrt{3}}{2} \), then \( A + A = I \), where \[ A = \begin{bmatrix} \sin\alpha & -\cos\alpha \\ \cos\alpha & \sin\alpha \end{bmatrix}. \]