House fly belongs to _____ family.

Assertion (A) is true. Cockroaches have compound eyes composed of many individual visual units called ommatidia. Each ommatidium captures a small portion of the visual fi eld, and the combined input from multiple ommatidia allows cockroaches to perceive a mosaic-like image of their surroundings.

Reason (R) is true. Mosaic vision provides cockroaches with a wide fi eld of view, high sensitivity to movement detection, and detection of changes in light intensity. But it has less resolution. Resolution depends on
factors such as the number of ommatidia and interommatidial angle. The tradeoff between sensitivity and resolution is a common feature of compound eyes in many insects, such as cockroaches.

Reason (R) does not explain (A). Cockroach can perceive several partial images of an object because the compound eye has several optically isolated ommatidia separated by pigment sheaths. Each ommatidium receives only a partial image of the object. Mosaic vision in insects is a result of evolutionary adaptation in insects to detect motion, changes in light, and other environmental cues necessary for their survival and reproduction.