How do shark brethe?

Sharks breathe through gills, which are specialized respiratory organs that allow them to extract oxygen from water. Sharks have five to seven gill slits on each side of their head, and each gill slit contains a series of gill filaments. The gill filaments are covered in tiny blood vessels, and as water passes over them, the oxygen in the water diffuses into the blood vessels. The oxygenated blood is then pumped throughout the shark's body.

Here's a more detailed explanation of the process of respiration in sharks:

1. Water enters the shark's mouth. As the shark swims, water enters its mouth and passes over the gills.

2. Gill filaments extract oxygen from the water. The gill filaments are covered in tiny blood vessels, and as water passes over them, the oxygen in the water diffuses into the blood vessels.

3. Oxygenated blood is pumped throughout the shark's body. The oxygenated blood is then pumped throughout the shark's body by the heart.

4. Carbon dioxide is released through the gills. As the blood passes through the gills, carbon dioxide diffuses out of the blood vessels and into the water.

Sharks are obligate ram ventilators, which means that they must constantly swim in order to breathe. If a shark stops swimming, water will stop flowing over its gills and it will suffocate.

Some sharks have adapted to breathe in different ways. For example, the nurse shark has a spiracle, which is a small opening on the top of its head that allows it to breathe air when it is resting on the bottom of the ocean. The great white shark has a unique circulatory system that allows it to maintain a high body temperature, which enables it to swim in cold waters where other sharks would not be able to survive.