How have humans affected the four spheres?

Human activities are impacting our environment and, in particular, the composition of the atmosphere, water, and plants. However, it is sometimes difficult to distinguish the "natural" signature from the one induced by industrial and urban activities. The latest analytical developments allow the fine and precise measurement of isotopic signatures of elements whose content or isotopic composition may be changed by modern industrial activities, such as the transition metals (Ni, Hg, Se, and Zn), lithium, and helium. This approach opens up original and new avenues of inquiry, including the determination of the sources of aerosols, of the elements carried by rivers, the effects of bioaccumulation, the phytoavailability of metals, and allows the refinement of the determination of anthropogenic fluxes.

answer; /// i do believe its (heredity); good luck

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.