The first sentence is true
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.
Answer:
A dolphin or whale.
Explanation:
It is a mammal, but is mistaken for a fish since it lives in the water.
Chemicals from sea slugs may be useful in <span>sewage treatment plants.
</span>The sewage treatment plants process includes <span> removing contaminants from wastewater, primarily from household sewage. </span>
The output of the sewage treatment process is treated wastewater that is safer for the environment.