Becuase they were fully aquatic unlike tetrapods today
Answer:
-Your lungs are part of the respiratory system, a group of organs and tissues that work together to help you breathe. The respiratory system's main job is to move fresh air into your body while removing waste gases.
- When you inhale, air enters your lungs and oxygen from the air moves from your lungs to your blood. At the same time, carbon dioxide, a waste gas, moves from your blood to the lungs and is exhaled.
-The circulatory system delivers oxygen and nutrients to cells and takes away wastes.
-The heart is divided into four chambers consisting of two atria and two ventricles, the atria receive blood, while the ventricles pump blood. The right atrium receives blood from the superior and inferior vena cavas and the coronary sinus, blood then moves to the right ventricle where it is pumped to the lungs.
-Systemic circulation carries oxygenated blood from the left ventricle, through the arteries, to the capillaries in the tissues of the body. From the tissue capillaries, the deoxygenated blood returns through a system of veins to the right atrium of the heart.
- Your blood is made up of liquid and solids. The liquid part, called plasma, is made of water, salts, and protein. Over half your blood is plasma. The solid part of your blood contains red blood cells, white blood cells, and platelets.
:) hopefully this helps lol
Explanation:
95% occurs in the small intestine.
Answer:
Organisms need carbon for building cells and energy to fuel the process; eukaryotes, in general, all follow the same basic metabolic pathways whereas prokaryotes use a variety of materials and pathways—some employed by no other organisms.
Explanation:
