<em>For example,</em>
<em> consider a mountain whose summit is 5,000 feet (1,500 m) in elevation, but somewhere on the way up, the trail goes back down 250 feet (76 m). ... </em>
<em>If one hikes over five hills of 100 vertical feet each, the cumulative elevation gain is 5 × (100 feet (30 m)) = 500 feet (150 m).</em>
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The ridge of a birds breastbone is called a keel
Three of the major characteristics used to classify organisms are cell structure, mode of nutrition and cellularity. These characteristics help scientists determine how organisms are similar to each other as well as how they are different from each other.
Answer:Primary reinforcers
explanation reinforcers that have innate reinforcing qualities.
