16. Which of the following statements best describes a commensal symbiotic relationship between two species? Both species benefit. One species benefits and the other is unaffected. One species benefits and the other is harmed. Both species are harmed.
17. The fundamental niche of an organism is determined by ______ factors, while the realized niche is determined by ______ factors. biotic; abiotic abiotic; biotic biotic; biotic abiotic; abiotic
18. Competition between species can be reduced as a result of character displacement. This is because one of the species becomes extinct. the species will no longer compete for the same resource. the niche of at least one of the species is changed. Both B and C are correct.
19. When they winter in Central and South America, robins form flocks and feed on fruit. During the summer, they migrate to North America, where they feed on caterpillars, earthworms and other animals. These birds are best described as herbivores. omnivores. detrivores. carnivores.
20. For your final examination before you receive your degree from Penn State, you have been given a slide that contains an unknown tissue from a multi-cellular eukaryote. You have been asked to identify if that tissue is from an animal, a fungus, or a plant. As you stare through the microscope at the slide, you remember that you learned the major differences between these cells in Biology 11. You look for the presence of ______, found only in plant cells, and the absence of ______, never seen in animal cells. But, the cells that you are looking at have a cell wall and do not have chloroplasts. You confidently circle ______ on the answer sheet. chloroplasts; mitochondria; animal mitochondria; chloroplasts; animal chloroplasts; cell walls; fungus mitochondria; cell walls; fungus
