Answer: Option B.
A see saw, chin raise.
Explanation:
A lever is a machine that can rotate and consist of a beam which is pivoted to fulcrum.
There are three classes of lever, the first class lever, second class lever and third class lever. These three classes of lever are classified base on the positions of effort, fulcrum and Load.
In first class lever, fulcrum comes between the effort and load. Examples is scissors , see saw, pliers. This is because effort is applied on the one side of the fulcrum and load is on the other side. Therefore, the childhood demonstration of first class lever motion is see saw and chin raise.
In the second class lever, load come between effort and fulcrum e.g wheelbarrow, bottle opener.
In the third class lever, effort comes between fulcrum and load e.g hammer, broom.
Answer:
Option B, Middle ear
Explanation:
Nasopharynx is the upper part of throat which lies behind the nose and it connects the to middle ear. It moves the mucus produced in the middle ear to the throat which is then further drained out.
This tube is responsible for equalizing the pressure inside the ear to the pressure outside the ear. It comprises upper throat and rear side of nasal cavity.
Hence, option B is correct
Answer:
D
Explanation:
Placed near window and placed in closet.
Answer:
Yes
Explanation:
In the atmospheric pressure present at sea level, water boils at 100 °C (212 °F). At an altitude of 63,000 feet (19,000 m), it boils at only 37 °C (99 °F), the normal body temperature of humans. This altitude is known as Armstrong's Line. In practice bodily fluids do not boil off at this altitude.
Answer:
Global warming is the unusually rapid increase in Earth's average surface temperature over the past century primarily due to the greenhouse gases released by people burning fossil fuels.
