<span>Organism's habitat (where a species live) can be described as all of the biotic and abiotic factors in the area where an organism lives.
b. Ecological niche (how species live) is composed of all of the physical, chemical, and biological factors that a species needs to survive, stay healthy and reproduce. The niche includes food, abiotic conditions, and behavior.</span>
The smallest unit of matter that has the characteristic properties of it’s element is called an “atom”.
Individual atoms are called “elements” for that reason.
There are smaller divisions of matter, however those no longer have the characteristics of the element that they may be a part of. A hydrogen electron is indistinguishable from an argon electron, or any other.
The four important characteristics of respiratory surface are:
1. Thin walls
2. Moisture
3. Large surface area
4. Blood supply
Respiratory system or respiratory tract is divided into upper and lower tract. Upper respiratory tract includes nose and its cavities, sinuses, pharynx and the part of the larynx. Lower respiratory tract consists of the trachea, bronchi, bronchioles and the alveoli.
Alveoli are the ends of the respiratory tract the smallest units in it. Alveoli are small folded air sacs that are branching off from alveolar ducts and providing an extremely large surface area for the gas exchange. Gas exchange occurs thanks to small blood vessels – capillaries that surround alveoli and it occurs via the process of diffusion.
So, respiratory surface is thin membrane also known as the blood–air barrier that consists of the alveolar epithelial cells, their basement membranes and the endothelial cells of the alveolar capillaries.
