Your goal during this activity is to design an experiment to determine the effect of a single independent variable (either pH or temperature) on the activity of catalase enzyme. Watch the video below and explore the things you can vary, and what you can measure. Use the tools button in the upper right hand corner of the screen and the menu bar along the bottom of the video. What tools are available for you to measure with? What possible pH values can be used during the experiment? At which temperatures can the experiment be performed?.

format change of dna.  

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.