Because of counter-current exchange, fish gills are the most efficient at gas exchange. This is followed by the continuous flow of bird lungs (due to their system of air-sacs). I don't know which animal exactly, but look to the fish for your answer.
Reptiles
I would argue that the Albatross is one of the most efficient animals. It does not have to flap it's wings when it soars across the oceans since it's wing bones lock into place. It is also able to sleep while flying. It has a glide efficiency of 20 feet forward for every 1 foot down.
It is a group of organs.
respiratory system
The Respiratory system,The Circulatory system,and The Urinary system.
The respiratory system is the group of organs within your body that enables you to breathe. The circulation system circulates blood throughout your body,
it's the mammal
group of cells = tissue group of tissues = organ group of organs= organ system eh respiratory system, skeletal system, muscle system
An Organ system can be defined as in Biology, a Biological system(or organ system) is a group or organs that work together to perform a certain task. Common systems such as those present in mammals and other animals, seen in human anatomy, are those such as the circulatory system, the respiratory system, and the nervous system.
An Organ system can be defined as in Biology, a Biological system(or organ system) is a group or organs that work together to perform a certain task. Common systems such as those present in mammals and other animals, seen in human anatomy, are those such as the circulatory system, the respiratory system, and the nervous system.
group of organs and tissues that permits breathing
the term for a group of treatments designed to improve respiratory efficiency, promote expansion of the lungs, strengthen respiratory muscles, and eliminate secretions from the respiratory system.
The group of organs that take in oxygen from the air is called your respiratory system.