Val works as a paleoclimatologist in Alaska. While studying ice core samples, she identifies an increase in the isotopic ratio of oxygen 10,000 years ago. From this discovery, she knows that Earth's temperature at that time was

✓ Aside from

temperature, Val can also learn about

✓ from the ice cores. Val's data suggests that she's uncovered a glacial

climate for this time period. During a glacial climate, Val knows, there would have been

sea level, compared to what

she witnesses today.

c

explanation:

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.