In a survey of northern mountain ash seedlings in northern Ontario, researchers randomly placed eight 1.0 m by 2.0 m quadrats in a field that measured 100 m by 150 m. Estimate the population density and size if the researchers found 2, 0, 0, 8, 6, 1, 1, and 3 seedlings in the eight quadrats.

hydrogen is a compound or a single element and a element is a pure substence that cannot be separated into simpler subtances

clorine is a compound its a chemical substance that forms when two or more different elements combine

so both hydrogen and clorine are compounds

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.