Answer:
It has long been known that static pressure affects middle-ear function and conventional tympanometry uses variations in static pressure for clinical assessment of the middle ear. Middle-ear under-pressures tend to reduce the velocity magnitude more than do middle-ear over pressures.
The effect of middle-ear static pressure on the acoustic response of both structures is similar in that non-zero middle-ear static pressures generally reduce the velocity magnitude of the two membrane components in response to sound stimuli.
Answer:
The force that holds the gases in the sun. The force that causes a ball you throw in the air to come down again. The force that causes a car to coast downhill even when you aren't stepping on the gas. The force that causes a glass you drop to fall to the floor.
The structure of the skin is an effective barrier against bacteria. The multiple layers of epidermis, while can be invaded by foreign organisms, has a high turnover rate which means it is constantly shedding, therefore even the bacteria is shed protecting the body. Lastly, the skin's lipids maintain an acidic pH which slows and stops growth and replication of bacteria.
External skeleton is the correct answer. Hope this helps out !