Which of the following explains how scientists know that current global warming is related to human activities? Atmospheric carbon has increased much faster than in the past.
There were no greenhouse gases in the atmosphere in the past.
There was more methane in the atmosphere 6,000 years ago.
There is more water vapor in the atmosphere today than the past.

By comparing the observed and modeled patterns, scientists can positively identify "human fingerprints” and attribute a proportion of observed warming to human activities. These fingerprints are found in a diverse range of records from the atmosphere, the ocean, and Earth's surface

the fossil record provides evidence of a common ancestor to many species.

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.