The answer is B, sameness
The only independent variable in this experiment is the amount of nitrogen Sarah uses. All of the other variables are dependent on other factor and processes, but Sarah controls the amount of nitrogen that she uses for each plant.
Fish are cold-blooded or poikilothermic, meaning that their body temperatures vary with the surrounding temperature. During the cold of winter fish become less active. They find little pockets out of the way of fast moving water where they can stay still and conserve energy.
Answer and Explanation:
The use of pesticides and fertilisers leads to soil pollution. These are often not easily biodegradable and so they accumulate in the soil and kill soil organisms. Rain water run-off may carry such chemicals into streams,rivers and lakes. These toxic chemicals can eventually find their way into the tissues of different organisms associated with aquatic ecosystem.
The accumulation of silt due to poor cultivation along the river banks and the destruction of riverine leads to soil erosion. The deposition of silt near the mouth of river makes the water turbid and so impedes the penetration of sunlight. This affects the aquatic organisms and pollute the water.
