Imagine a system where a finch feeds on thistle seeds and the finch population size is linked to the productivity of the thistle, and the thistle population size is related to foraging pressure of the finch population. this is an example of population dynamics at the level. (a) population. (b) community. (c) ecosystem. (d) species.

Community.

Explanation:

Community may be defined as a group of population of two or more different species in a ecosystem. These population occupy the same geographical area and may or may not share the same resources.

The finch feeds on thistle population and the thistle population size is related to foraging pressure of finch population. Here, two populations are interacting with each other, this is a case of community.

Thus, the correct answer is option (B).

it has to be understood that the sea water contains a huge amount of sodium and chlorine ions and if they enter the cell of the atlantic cod fish, the cell will shrivel and the fish will die. to avoid such a condition, the fish uses active transport for the purpose of removing the ions against the gradient.

explanation:

the atlantic cod is not a maritime osmoconformer. its native application of salts is less than that of the seawater it lives in. it is continually falling water from the gills to the ocean via osmosis.

countering that, the fish is going to be swallowing seawater. but since its internal collection of salts is lower than seawater, the fish will want to go free of excess salt, and since that's going upon a gradient, then active transport, requiring energy, must be used to pump out the salt. much marine fish use the organs to filter out the salt and these fish discharge very straight urine.