A Swim Bladder is not present in cartilaginous fishes. Also called a fish maw or gas bladder the swim bladder is a gas-filled bladder that allows many bony fish to control their buoyancy by filling or releasing gas form the bladder. This allows them to change bouyancy without wasting metabolic energy by swimming.
I believe the answer is: The dark colored moths will experience disruptive selection
The bird prey on moth and possibly identify the moth by visual sense. The moth has two type of color: dark and light. The trees in the area is more light coloured so the black moth will be identified easier as their color is more contrast to the tree. As the dark moth easier to identify, they will be predated more and their population will be reduced. When a trait has advantage than the other, disruptive selection happens.
B, metals, nonmentals all bond to be stable
During the 32nd week of gestation, good luck!