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An ecosystem consists of the biological community that occurs in some locale, and the physical and chemical factors that make up its non-living or
abiotic environment. There are many examples of ecosystems -- a pond, a forest, an estuary, a grassland. Sometimes the boundaries are not obvious
but in a pond the drag and drop answer here becomes the boundary. One drag and drop answer here into the pond system is energy in the form of
sunlight. Energy moves through the trophic levels of the pond system. It is not recycled so this is an drag and drop answer here subsystem within the
pond. Nutrients, carbon, nitrogen, phosphorus, are recycled when an organism dies and decomposes. The pond is a drag and drop answer here
subsystem with respect to these nutrients,
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Cycling of Energy and Matter

the electric field is a “force field” around a charged object that illustrates the direction the electric force would push an imaginary 

russian is not my first language, so i'm afraid i can't write out an answer in russian, but hopefully you can find a way to do so. here's my best translation of the problem: you're given a plot of a particle's position in one-dimensional space over time, and you're asked to find either the total distance traveled by the particle after 6 seconds had elapsed, or the total displacement of the particle after 6 seconds.

if you want the total distance traveled, you would first need to determine the particle's velocity as a function of time, then integrate that over the 6-second interval. we know the position function is quadratic with roots at 0 and 6, so we have

where is unknown. because the position is parabolic, there is symmetry about the midpoint at , and we know that

so that the position function is

which means the velocity is

then the total distance traveled is

so the total distance traveled is 20 m.

on the other hand, if you want to find displacement: the particle starts at and ends at , so its displacement is 0.