Zach is conducting an experiment to observe which type of fertilizer will allow a plant to grow the tallest. He puts three plants in identical pots and places them in the same location. He waters the plants each day with the same amount of water. Then, Zach measures the plant growth and records his observations. Which of these is the control group in Zach’s experiment?

a) the growth rate of each plant
b) the pot that does not contain fertilizer
c) the type of fertilizer used in each plant
d) the amount of water given to each plant

primary succession begins with a bare rock and ends with a forest secondary succession begins after a natural disaster where there is a temporary setback after a forest fire or local destruction, but the surrounding area can fill in

blue stars have the highest surface temp

stellar distances are usually expressed in light-years

the measure of a star's brightness is called magnitude

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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.