The part of human eye which controls the amount of light entering into it is:
Step 1: Identifying the structure. The iris is the part of the human eye that controls the size of the pupil and, in turn, regulates the amount of light entering the eye.
Step 2: Conclusion. Thus, the correct answer is option (A): Iris.
In the adjoining figure, \( AP = 1 \, \text{cm}, \ BP = 2 \, \text{cm}, \ AQ = 1.5 \, \text{cm}, \ AC = 4.5 \, \text{cm} \) Prove that \( \triangle APQ \sim \triangle ABC \).
Hence, find the length of \( PQ \), if \( BC = 3.6 \, \text{cm} \).