Answer:
During metamorphosis, they undergo a change in body chemistry that enables them to live in salt water. In biology, metamorphosis is the process by which an animal develops continually, after birth or hatching. This involves the change in body structure; both internal and external features, regulated by hormones. Metamorphosis is occasionally accompanied by changes in the animal’s behaviour, physiology and biochemistry.
Step-by-step explanation:
During metamorphosis, they undergo a change in body chemistry that enables them to live in salt water. They change color during metamorphosis as well. The salmon must return to fresh water in order to spawn (breed). Fish that live in the ocean as adults but spawn in fresh water are anadromous. Lampreys go through a period of metamorphosis