Red squirrels and gray squirrels have been the native species on an island for many years. A few years ago, black squirrels entered this island. The black squirrel is an invasive species. Invasive species aren’t native to the ecosystem. They move into an ecosystem because of natural changes or human intervention. Red squirrels and black squirrels have identical food requirements, but gray squirrels have a different diet. What three effects will these events have on the island’s squirrel population?

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.

some scientists like gregory adcock agree with thorne's theory of regional continuity.

others, like chris stringer and ian tattersall, believe thorne's results may be contaminated or misinterpreted.

answer is d hope this

dna is a set of a gene held together by a chemical bond