Me this is due in 5 minutes
magnetism and fluorescence are both
a. connected to density
b. very common in minerals
c. special physical properties
d. to be dependent on cleavage

b) the inside picture would look at a very high temperature in a very low ph

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.