Answer:
The swim bladder is located in the body cavity and is derived from an outpocketing of the digestive tube. It contains gas (usually oxygen) and functions as a hydrostatic, or ballast, organ, enabling the fish to maintain its depth without floating upward or sinking.
Explanation:
THe base of the pyramid is built from organisms that primarily
A) are autotrophs.
The substance is called DNA.
Answer:
Ozone
Explanation:
Ozone is considered a pollutant in the troposphere, but in the stratosphere it is essential to life on earth because it absorbs biologically harmful UV radiation. The mesosphere and the thermosphere are two additional atmospheric layers above the stratosphere.
