If two sounds are at slightly different frequencies, beats can be heard at a frequency equal to the difference in frequency of the two sources.

Snakes, dogs, and humans have a vertebral column. snakes and dogs have tails, and humans have vestigial tailbones. dogs and humans have limbs, but snakes do not. most reptiles lay eggs, but a few give birth to live young. what do these structures suggest about the evolutionary pattern between the three organisms? 1. snakes and dogs are more closely related than snakes and humans. 2. snakes and humans are more closely related than humans and dogs. 3. dogs and humans are more closely related than snakes and humans. 4. dogs, snakes, and humans share a common ancestor. 5. the early ancestor of snakes and dogs is the same, and the early ancestor of humans is different.

The graph shows the populations of two species in a particular region over two decades. based on the graph, what can you conclude about the relationship between the two species? a. the two species have a parasitic relationship. b. the two species are mutualistic in nature. c. the two species exhibit commensalism. d. the two species have a prey-predator relationship. e. the two species have a familial relationship.

The tendency to seek out individuals who represent the same level of physical attractiveness as ourselves is explained as