Answer
lizards:reptiles::pandas:bears
Step-by-step explanation:
An analogy draws a relationship between two different things. The purpose is to compare those things by finding something that connects them, despite the differences. An example of relationship found in analogies is the performer-action relationship (actor:act; worker:work).
In the case we are analyzing here, lizards:reptiles, the analogy provided is a part-whole one. Lizards are a type of reptile, they are a group, a part that belongs to the whole. Thus, to complete the analogy, we need to find a pair that conveys the same logic. The best one is pandas:bears. Pandas are a type of bear. In the whole that is "bears", we have a group, a part that is "pandas".