Which of the following is true about impervious building materials?
a.
impervious surfaces prevent pollutants from entering the water supply.
b.
vegetation and gravel are common impervious materials.
c.
having fewer impervious surfaces improves water drainage.
d.
all of the above

The correct answer is C. Having fewer impervious surfaces improves water drainage.

Impervious surfaces are termed as artificial structures. For example, pavements, logistics, ports and airports.

They are being covered by impenetrable materials.

For example rooftops, stone, brick, asphalt, and concrete.

Pavement are good material which seals the soil surface so as to eliminate groundwater recharge and rainwater infiltration.

The correct answer is option C

Impervious materials can be defined as the materials that does not allows the water to move inside the ground (soak). Some natural surfaces can be relatively impervious like compacted clay.

Having fewer impervious surfaces improves water drainage of the roads. It actually repels the rainwater and does not allows infiltration of water.

This helps to improve water drainage system.

answer: decrease

a limiting factor is the one which decrease the abundance, distribution and causes extinction of the population of species in a ecosystem. here, predators including hawks, owls and snakes are the limiting factor for the population of mexican free tailed bat.   although bats are nocturnal animals as they forge for food at night these predators also may remain active during night which can decrease the population of the mexican free-tailed bats. also, these bats eat only one type of insects that are moths. the food can also be a limiting factor as all 400 members are dependent upon same type of food needs that are moths. the decrease in the moth population can cause decrease in population size of the mexican free-tailed bats.

therefore, the scenarios will most likely to decrease the population size of the mexican free-tailed bats.  

oxygen = 21% of the atmosphere

nitrogen = 78%

carbon dioxide = 0.1%

argon =0.934%