3. Banking stem cells is a very popular practice in science. This is when stem cells, located in the umbilical cord of a birthed infant, are saved and frozen. Why could this be a beneficial practice? Stem cells are undifferentiated and therefore, could be used to grow into any kind of cell of the body
In case of an emergency, it is always good to have a lot of cells on hand since they cannot replace themselves
Stem cells should not be saved because all cells of the body can be used as stem cells
Stem cells are already differentiated but can still replace different cells located in the body

from my research i have to the conclusion that decomposers, such as fungi, bacteria and invertebrates, play a critical role in nutrient cycling and without them the earth's ecosystem may not support life as we know it. elements such as carbon, nitrogen and phosphorus exist in limited amounts on earth, although huge amounts of carbon are being released into the atmosphere from underground sources now by humans. it is still extremely important that other nutrients be retained by the process of re-use. decomposers are organisms that are able to chemically break down dead material and make these elements available for use by other organisms. without this breakdown of dead material, dead bodies would pile up. so decomposers also play a role in clean up also. without them, life might not continue as we know it and dead material would overwhelm the earth.    

the answer is true when observing or determining population size, a direct observation is use, in which each organism is counted in a population or in an area. one benefit of this measure is that you get the exact population count but it will take a long time to  determine  the  size  of a  population.