the minimum quantity of energy that the reacting species must possess in order to undergo a specified reaction.
Collagen Fiber. this is the strongest and most common connective fiber; it has tensile strength; its appearance is long, straight, and unbranched; examples: tendons and ligaments. reticular fiber.
Explanation:
Why (for what reasons) is it believed that oxygen was not present when life formed on Earth? The life forms were anaerobic, and did not make oxygen. There is a lack of oxidized iron in rocks that are a few billion years old. Eventually oxygen from the oceans moved into the atmosphere, and iron could be oxidized.
The part of the human ear that conducts air between the middle ear and the back of the throat to equalize pressure on either side of the eardrum is called the eustachian tube.
Eustachian tube connects the middle ear with the nasal cavity. It allows pressure release of the middle ear, preventing trauma that caused by high pressure differences called barotrauma. Eustachian tube is normally closed to prevent bacteria inside nasal cavity enter the ear. It only opened in a certain condition like swallowing.
