Actually it is the females the mostly build the nests the males will help build it sometimes both males and females will build it but typically it is females and that goes for all birds.
"Females typically build nests, but sometimes both parents or just the male"
A difference between coelom and Pseudocoelom is that the gut of a pseudocoelom is surrounded by the endoderm, and the gut of a coelomate is surrounded by the ectoderm. So your answer is D.
None, the answer would be 2500
Because of underdeveloped lungs the frog has to breathe through moist skin. Therefore for exchange of gases the skin is thin and moist