What characteristic signifies superior quality when candling eggs?

The characteristic that signifies superior quality when candling eggs is a slightly defined yolk outline. When the yolk is clearly visible and well-defined, it indicates that the egg is fresh. A fresh egg will have a firm, centered yolk that does not spread too much when candled. This is a desirable quality because it suggests that the egg's protein has not lost its integrity over time, which can happen as the egg ages. As eggs age, the contents can become more fluid, causing the yolk to spread and making its outline less distinct.

The other options, while they may contribute to egg quality, do not specifically indicate superior quality in the same way. A strong eggshell is generally a good characteristic, as it provides protection, but does not directly reflect the internal quality of the egg. Uniform color can also be indicative of quality but is more related to the breed of the laying hen rather than the freshness or internal quality of the egg. A large air cell can suggest that an egg is older, as the air cell enlarges over time due to moisture and air loss, which would indicate a decline in quality rather than superior quality. Therefore, among the options provided, a slightly defined yolk outline is the best indicator of a high