An example of a mutualistic association between a plant and a fungus would be

mycorrhiza

Explanation: mycorrhiza is the symbiotic relationship that occurs between a fungi and the root of plants.here the fungi helps the plant absorbs nutrients and water from the soil.the fungi encloses the root and it's hyphae penetrates into the root cell.the fungi in return gets food from the plant.in this interaction,they both benefit.

The association may be ectomycorrhizal or endomycorrhizal. In ectomycorrhizal,the fungi grows on the surface of the root and it's hyphae coats the roots.in endomycorrhizal,the fungus does not necessarily coat the root,but few hyphae penetrates the epidermal cell and the cortex of the root.it is said to be living within the cells of the root.

explanation:

the universal gravitation equation. since the gravitational force is directly proportional to the mass of both interacting objects, more massive objects will attract each other with a greater gravitational force. if the mass of one of the objects is doubled, then the force of gravity between them is doubled.

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.