Many people keep a compost pile in their backyards. They use the compost as fertilizer for their flower beds. Which of the following correctly describes the disposal of waste by composting? A.
Yard wastes such as grass clippings are not suitable for composting because they contain low levels of nutrients.
B.
Composting reduces the amount of waste sent to landfills by restaurants, food-processing plants, and animal feedlots.
C.
Compost made from glass and plastics can be recycled and used as building materials.
D.
Composting is a good way for individuals to reduce the amount of garbage they send to the landfill, but large-scale composting is impractical.

statement #3 on andre"s list is false.

speed of light in vacuum is 300,000 km/s

speed of light in other mediums is given by the expression v = c/n, where c is the speed of light in vacuum and n is the refractive index of medium.

for the first medium v = 200,000 km/s

  so, refractive index of medium = 300000/200000 = 1.5

    1.5 refractive index is usually for glass. so first medium is glass.

for the second medium v = 250,00 km/s

so, refractive index of medium = 300000/250000 = 1.2

    1.2 refractive index is usually for water. so second medium is water.

for the third medium v = 0 km/s

so, refractive index of medium = 300000/0 = ∞

    ∞ refractive index is usually for opaque mediums. so third medium is opaque medium.