Answer:
If the petri plates are kept open for the longer duration of time then there are chances of cross contamination.
The contamination can be defined as growth of undesired microbes in the petri dishes or tubes which is no longer useful for the experiment.
The tube if kept open will develop the growth of contaminants in it. It can be cross contamination as well.
To avoid contamination the tubes and dishes should not be kept open for a longer duration of time.
This is the starting molecule for cellular respiration and an important source of energy in cells.
The answer is omnivore, because it eats plants and animals
They do not influence the salinity level in their environment, they maintain the salinity in their body. If they don't, osmosis will cause their cells to shrink due to the fact that the salinity in the cell is lower than outside the cell. This will make water leave the cells. So they need to get rid of excess salt all the time. Freshwater fish need to retain the salt in their bodies, otherwise the opposite will happen. Salinity level in the cell is higher than outside the cell and this causes influx of water which will make the cell build up turgor pressure. Ultimately they will explode. So fishes in both environments adapted to deal with osmosis.
