Dolphins are animals that live in water, but they do not have gills. What might this suggest about dolphins?(1 point)

Responses

They do not need oxygen.
They do not need oxygen.

They do not need to release carbon dioxide.
They do not need to release carbon dioxide.

They make their own food.
They make their own food.

They have another structure to obtain oxygen.

They have another structure to obtain oxygen.

Which of the following is one response to higher temperatures in a habitat?(1 point)

Responses

thicker fur
thicker fur

more movement
more movement

more fat storage
more fat storage

more sweating

more sweating

Why is fever an effective response to pathogens?(1 point)

Responses

It can remove pathogens from the body.
It can remove pathogens from the body.

It can signal the body to fight.
It can signal the body to fight.

It can inactivate pathogens in the body.
It can inactivate pathogens in the body.

It can signal the body to run.
It can signal the body to run.

It can inactivate pathogens in the body.

They have another structure to obtain oxygen.

To understand why dolphins, as water-dwelling animals, do not have gills, we can examine their respiratory system. Dolphins are mammals, which means they have lungs and breathe air, just like humans. Unlike fish that have gills to extract oxygen from water, dolphins have evolved a different structure to obtain oxygen.

Dolphins have a specialized adaptation called a blowhole, which is located on the tops of their heads. The blowhole acts as a nostril, allowing dolphins to breathe air when they come to the water's surface. When a dolphin surfaces, it opens its blowhole and exhales, releasing carbon dioxide, and then quickly inhales fresh air. This adaptation enables dolphins to take in oxygen and expel carbon dioxide without the need for gills.

Therefore, if dolphins do not have gills but still live in water, it suggests that they have another structure, namely the blowhole, through which they can obtain oxygen from the air above the water's surface.