Students hypothesized that water pollution affects the growth of fish. In an experiment, they added the same amount of food to 2 ponds polluted by fertilizers and industrial waste. They measured fish growth and found that most fish grow slowly in each of these environments. Why is their conclusion not reliable?

If bacteria are much too small to see, what is one reason why can we see colonies in the petri dishes that have plenty of food to eat after only a few days?

Is there any solid scientific evidence that humans have been cloned?

Juan and carol were studying invertebrates in biology. they knew that segmented or earth worms preferred a dark, moist habitat. during this lab, they would be investigating the responses of organisms called planaria or dugesia tigrina. these were simple flatworms that still had a one-way digestive system and a very simple nervous system. juan and carol placed the planaria in a petri dish containing cool, distilled water that was partially covered with black paper. they shined a light on the dish. next, they removed the paper and placed a small amount of chicken liver at one end of the dish. they added a few large salt crystals to the water. finally, they added drops of hot water to the cool water in the petri dish. their results can be seen in the data table. according to their experiment, all but one conclusion is valid.