Which of the following statements comparing respiration in fish and in mammals is correct?

• A. Both fish and mammals use lungs as their primary respiratory organs.
• B. Fish and mammals both rely on diffusion through their skin as the main method of gas exchange.
• C. Mammals extract oxygen from water using gills, while fish extract oxygen from air using lungs.
• D. Fish use gills to extract oxygen from water, while mammals use lungs to extract oxygen from air.

Answer: (D)

Verified step by step guidance

1. Understand the primary respiratory organs used by fish and mammals. Fish use gills, which are specialized structures for extracting oxygen from water, while mammals use lungs to extract oxygen from air.
2. Recognize the differences in the medium of gas exchange. Fish rely on water as the medium for oxygen extraction, whereas mammals rely on air.
3. Learn the mechanism of gas exchange in gills. Gills have thin filaments with a large surface area, allowing oxygen to diffuse from water into the blood and carbon dioxide to diffuse out.
4. Understand the mechanism of gas exchange in lungs. Mammals have alveoli in their lungs, which provide a large surface area for oxygen to diffuse from air into the blood and carbon dioxide to diffuse out.
5. Compare the correct statement with the incorrect options. Fish do not use lungs, mammals do not use gills, and neither group relies primarily on diffusion through the skin for gas exchange. The correct statement is: Fish use gills to extract oxygen from water, while mammals use lungs to extract oxygen from air.