2. There are many different types of cancer. Which of the following is one thing they all have in common?
a. They are all caused by uncontrolled cell death.
b. They all start in the lungs and migrate to different parts of the body.
c. They are all caused by uncontrolled cell growth.
d. All of the above
e. None of the above

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.

i think the answer is a.keratin is the pigment responsible for skin color.