The first step in sensation for some sensory systems is the , which modify incoming stimuli. Sensory receptors accessory structures absolute thresholds thermoreceptors.

allowed for the prediction of the properties of missing elements.

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.

answer; three;