Final answer:
A wooden spoon is an example of an opaque object, as it does not allow light to pass through, unlike a drinking glass, window glass, or wax paper which are transparent or translucent.
Step-by-step explanation:
The question asks to identify which object is completely opaque. An opaque object is one that does not allow any light to pass through it; it is the opposite of transparent. Referring to the provided details, a wooden spoon is an example of an opaque object because it does not allow light to pass through, thereby making it impossible to see through the spoon. On the other hand, transparent objects such as a Petri dish made of plastic or glass, a drinking glass, and window glass allow a high proportion of light to transmit through them, making it possible to see the other side. Wax paper allows some light to transmit through it but diffuses the light, making it translucent, not completely opaque.