Solutions hypertonic to bacteria and fungi are used for food preservation. for instance, jams and jellies are hypertonic with sugar, and pickles are hypertonic with salt. how do hypertonic solutions kill bacteria and fungi that would otherwise spoil these foods?

Hypertonic solutions, create an environment where food's cells dehydrate preventing the growth of bacteria and fungi. Also, these solutions could create an extreme environment and would kill microbes or limit their growth.

Explanation:

Osmosis is the movement of water through a semipermeable membrane from an area of low solute concentration to one of higher solute concentration to establish an equilibrium. The solutes are solids that dissolve in water and form ions, such as salts (NaCl) and sugars, these solutes are also found the cell’s cytoplasm.

Cells in food have a cell membrane, which allows the net flow of water inside or outside the cell through the osmosis process, depending on the amount of solute in the medium and the amount of solute in the cell’s cytoplasm, this is called osmolarity. A hypertonic solution is a solution with a higher concentration of solutes in the extracellular fluid than on the inside, which means there is a high osmolarity, therefore, water will move out of the cell, causing it to shrink and dehydrate. When water leaves the cell, the growth of fungi and bacteria is prevented from preserving the food. Also, a high hypertonic environment could kill microbes or slow their ability to reproduce.

estuaries are the partially enclosed coastal bodies of brackish water formed at the mouth of sea where river meets an ocean. it is a transition zone between river and sea water so estuaries are influenced to both marine environment such as tides, waves and to riverine such as flow of fresh water and sediments. the mixing of sea and fresh water provide high level of nutrients, making estuaries a high product habitats.

many estuaries suffers degradation from a variety of human activities like erosion from deforestation, overgrazing, overfishing, drainage and eutrophication.

so from the above statement answers will be

1. false as estuaries are formed due to both brackish and freshwater.

2.true, due to high productivity estuaries are breeding ground for many marine species.

3. direct and indirect activities of man that contribute to pollution and deposition of sediments.