A scientist claims that a certain chemical will make fabric waterproof. Which option describes a controlled experiment that will produce evidence that will
support or refute her claim?
A. Two groups of fabric are treated with the chemical. One group is
cotton and the other is polyester. Then each group is exposed to
water.
B. One group of fabric is treated with the chemical, and the other
group is not. Then each group is exposed to water.
C. One group of fabric is treated with a small amount of the
chemical, and the other group is treated with a large amount. Then
each group is exposed to water.
O D. Two groups of fabric are treated with the chemical. Then one
group is exposed to a small amount of water, and the other group
is exposed to a large amount.

C. One group of fabric is treated with a small amount of the

chemical, and the other group is treated with a large amount. Then

each group is exposed to water.

as we probably am aware that our atmosphere or air have various levels, each level has different gasses, and each gas has another porousness. at the point when the light originates from lower porousness to higher penetrability, it alters its course. with the goal that implies that when the light originates from the moon to the earth, it alters it's course a lot more occasions. it essentially implies that the state of the light piece of the moon is changed on the earth.

not copied too! hope this !

joke:

h o h o hope you have a merry christmas!

snell's law

refractve index = sin incidence / sin refraction