Answer:
The respiratory system is a biological system consisting of specific organs and structures used for gas exchange in animals and plants. The anatomy and physiology that make this happen varies greatly, depending on the size of the organism, the environment in which it lives and its evolutionary history. In land animals the respiratory surface is internalized as linings of the lungs. Gas exchange in the lungs occurs in millions of small air sacs called alveoli in mammals and reptiles, but atria in birds. These microscopic air sacs have a very rich blood supply, thus bringing the air into close contact with the blood. These air sacs communicate with the external environment via a system of airways, or hollow tubes, of which the largest is the trachea, which branches in the middle of the chest into the two main bronchi. These enter the lungs where they branch into progressively narrower secondary and tertiary bronchi that branch into numerous smaller tubes, the bronchioles. In birds the bronchioles are termed parabronchi. It is the bronchioles, or parabronchi that generally open into the microscopic alveoli in mammals and atria in birds. Air has to be pumped from the environment into the alveoli or atria by the process of breathing which involves the muscles of respiration.
Explanation:
Answer:
add plants and trees
Explanation:
they help hold the soil in place because of their roots
Answer:
Active transport requires cellular energy for substances to cross the cell membrane; passive transport does not.
Explanation:
Active Transport works against the concentration gradient and therefore needs energy to make it happen
Passive transport such as Diffusion and Osmosis uses the properties of natural movement of particles which moves the molecules from areas of high concentration to areas of low concentration or down the concentration gradient and happens passively without the need for energy
Filling of the heart and needing to pump the blood back out at an also increased rate
