Concept:Environmental and management factors can lower egg weight, but physical traits like comb size do not directly cause this reduction.
Explanation:High environmental temperature causes heat stress in layers.
Heat stress reduces feed intake, which leads to lower egg weight.
Poor lighting reduces hormonal stimulation and feed consumption.
This also negatively affects egg production and egg weight.
Comb size is related to maturity and bird condition, not a direct negative factor.
Thus, factors I and II have a negative influence on egg weight.
Answer:A. I and II only