<em><u>Invertebrat</u></em><em><u>e</u></em><em><u> </u></em><em><u>means</u></em><em><u> </u></em><em><u>those</u></em><em><u> </u></em><em><u>organism</u></em><em><u> </u></em><em><u>which</u></em><em><u> </u></em><em><u>doesnot</u></em><em><u> </u></em><em><u>have</u></em><em><u> </u></em><em><u>backbone</u></em><em><u> </u></em><em><u>in</u></em><em><u> </u></em><em><u>their</u></em><em><u> </u></em><em><u>body</u></em><em><u> </u></em><em><u>.</u></em><em><u>Some</u></em><em><u> </u></em><em><u>of</u></em><em><u> </u></em><em><u>t</u></em><em><u>he</u></em><em><u> </u></em><em><u>examples</u></em><em><u> </u></em><em><u>are</u></em><em><u>:</u></em>
<em><u>1</u></em><em><u>.</u></em><em><u>S</u></em><em><u>p</u></em><em><u>i</u></em><em><u>d</u></em><em><u>e</u></em><em><u>r</u></em>
<em><u>2</u></em><em><u>.</u></em><em><u>e</u></em><em><u>a</u></em><em><u>r</u></em><em><u>t</u></em><em><u>h</u></em><em><u>w</u></em><em><u>o</u></em><em><u>r</u></em><em><u>m</u></em>
<em><u>3</u></em><em><u>.</u></em><em><u>S</u></em><em><u>t</u></em><em><u>a</u></em><em><u>r</u></em><em><u>f</u></em><em><u>i</u></em><em><u>s</u></em><em><u>h</u></em>
<em><u>4</u></em><em><u>.</u></em><em><u>S</u></em><em><u>e</u></em><em><u>a</u></em><em><u> </u></em><em><u>urchins</u></em><em><u>.</u></em>
<em><u>hope</u></em><em><u> </u></em><em><u>this</u></em><em><u> </u></em><em><u>will</u></em><em><u> </u></em><em><u>help</u></em><em><u> </u></em><em><u>u</u></em><em><u> </u></em><em><u>a</u></em><em><u> </u></em><em><u>lot</u></em><em><u>.</u></em><em><u>.</u></em><em><u>.</u></em><em><u>.</u></em>
<h2>
Answer: an underground lake</h2>
Explanation:
In general, sound (mechanical waves) travels faster in solids than in liquids, and faster in liquids than in gases. This is because <u>the speed of the mechanical waves is determined by a relationship between the elastic properties of the medium </u>in which they are propagated and the mass per unit volume of the medium (that is:<u>density</u>).
In other words: The speed of sound varies depending on the medium through which the sound waves travel.
So, if we are told the sound wave initially had a speed of 4,000 m/s and it suddenly decreases to 1,500 m/s, this means the sound waves passed from a solid medium to a liquid medium.
Hence, the correct option is: an underground lake.
<span>Divergent plate boundaries are locations where plates are moving away from one another. This occurs above rising convection currents. The rising current pushes up on the bottom of the lithosphere, lifting it and flowing laterally beneath it. This lateral flow causes the plate material above to be dragged along in the direction of flow. At the crest of the uplift, the overlying plate is stretched thin, breaks and pulls apart. hope this helps
</span>
Average speed = (total distance covered) / (time to cover the distance)
Total distance = (80m) + (125m) + (45m) = 250 meters
Overall time = 10 minutes
Average speed = (250 meters) / (10 minutes)
<em>Average speed = 25 meters/minute </em>
Since we're only looking for average speed and not velocity, we don't care about any of the directions, and we don't need to calculate Mary's displacement.