1. Enterococcus and coliforms can enter the water through feces. Although a water sample is negative for these bacteria, it could still be infected by pathogens from other sources than feces.
2. Culture media are sterilized by filtration because they could contain antibiotics or serum which deteriorate upon heat. Filtration is used in sanitation to remove large particles.
3. In the membrane filter technique, it is assumed that <span>all viable bacteria will form colonies. This means that formed colonies develop from the viable bacteria so that the number of colonies suggests the number of bacteria.
4. E. coli is negative for Citrate and Voges-Proskauer tests, and is positive for Indole and Methyl red tests.
5. The answer is yes because eo</span><span>sin-methylene blue agar is inhibitory to Gram+ bacteria.</span>
The tundra and the savanna desert
Answer:
<em>The correct option is D) How is the number of frogs in Massachusetts affected by pollution</em>
Explanation:
A scientific question can be described as a question which can be answered through the scientific method of research. Based on the scientific question, a hypothesis can be formulated. For example, for the option D, the hypothesis can be 'if the pollution increases, then the number of frogs decreases.' A hypothesis is a tentative statement which can be tested through experiments. Based on these experiments, results are formulated and conclusions are drawn. The question mentioned in option D can be answered through this method hence, it is the correct option.
The atmosphere
Is not a reservoir for phosphorus.
