Daphnia are small water fleas that are relatively transparent and thus their heart beat can be monitored under a microscope. In a series of experiments, 3 different Daphnia fleas were exposed to either water (control) or dilute solutions of different drugs (shown in the table below). After a brief period of equilibration after exposure to the drug, the heartbeat of the flea was counted for 1 minute and recorded in the table below: Control Adrenaline Nicotine Alcohol Caffeine Flea 1- 50 80 30 27 38 Flea 2- 28 74 35 28 24 Flea 3-- 55 64 34 27 50

frogs. the lower the ph the higher the acid content. frogs have the highest tolerance in this scenario.

genetic variation will increase because of a new habitat and food source.

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.