the answer is rust so the answer is rust
hi, so the material that would normally form mineral crystals does not have time to form a crystalline structure because of very rapid cooling after volcanically erupting into the air or onto the surface. Obsidian is a volcanic glass.
Answer:
The image distance is 17.56 cm
Explanation:
We have,
Height of light bulb is 3 cm.
The light bulb is placed at a distance of 50 cm. It means object distance is, u =-50 cm
Focal length of the lens, f = +13 cm
Let v is distance between image and the lens. Using lens formula :

So, the image distance is 17.56 cm.
When looking for distance you multiply speed by time
So 15 x 2 = 30
30 is the distance between his house and school
If a red blood cell is 7 x
m in size, it means that such a cell is 7 microns or micrometer in size. The unit that completes the sentence will, thus, be microns or micrometer.
According to international system of measurement:
m = decimeter
m = centimeter
m = millimeter
m = micrometer or micron
m = nanometer
Thus, a measurement of 7 x
m is the same is 7 micons or 7 micrometer.
More on metric conversion can be found here: brainly.com/question/17767575