What are gills? what purpose do they serve in fish?

Gills extract out oxygen from water and carbon dioxide is carried away by water. With the help of gills fish force the water, they flow past lots of tiny blood vessels. There is a seeping of oxygen through blood vessels wall and carbon dioxide is taken out. With gills water flow through their mouth over the gills and taken out with the helps of gill slits. Because water is heavier  and water moves in one direction.

Explanation:

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.  

idk why hjggjhjkhj