The answer is the first one
D. It provides buoyancy to a fish.
This air pocket is known as the swim bladder, and also called air bladder. This is a buoyancy organ possessed by most bony fish. The air bladder is located in the body cavity and is derived from an out pocketing of the digestive tube.
The key difference between age polyethism and reproductive division of labor in honey bees is their age and functions, younger bees work inside the honeycomb, they have several duties, such as feeding the larvae, cleaning, thermoregulate the inside and receiving the nectar from the older bees, through trophalaxy (mouth contact), those bees are in charge of the guard an cleaning of the outside, besides helping with the honeycomb ventilation.
Answer: Hydrogen
Explanation:
Hydrogen gas (H2) is a molecule, but not a compound because it is made of only one element. Water (H2O) can be called a molecule or a compound because it is made of hydrogen (H) and oxygen (O) atoms.
