Answer the following question given this paragraph: Competitive Exclusion Principle Resources are often limited within a habitat and multiple species may compete to obtain them. All species have an ecological niche in the ecosystem, which describes how they acquire the resources they need and how they interact with other species in the community. The competitive exclusion principle states that two species cannot occupy the same niche in a habitat. In other words, different species cannot coexist in a community if they are competing for all the same resources. An example of this principle is shown in Figure 45.24, with two protozoan species, Paramecium aurelia and Paramecium caudatum. When grown individually in the laboratory, they both thrive. But when they are placed together in the same test tube (habitat), P. aurelia outcompetes P. caudatum for food, leading to the latter's eventual extinction. Q: Which principle states that two species cannot occupy the same niche in a habitat? Choices: - complete exclusion - produce exclusion - tough exclusion - competitive exclusion A:
competitive exclusion
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Answer the following question given this paragraph: Nonvascular plants were the first plants to evolve. Compared to other plants, their small size and lack of specialized structures, such as vascular tissue, stems, leaves, or flowers, explains why these plants evolved first. The first nonvascular plants to evolve were the liverworts. The hornworts evolved somewhat later, and mosses apparently evolved last. Of all the bryophytes, mosses are most similar to vascular plants. Presumably, they share the most recent common ancestor with vascular plants. Q: What type of plants were the first to evolve? Choices: - vascular - kilocalorie - cocklebur - nonvascular A:
nonvascular
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Answer the following question given this paragraph: Early vertebrates were ectothermic. Ectothermy means controlling body temperature to just a limited extent from the outside by changing behavior. For example, an ectotherm might stay in the shade to keep cool on a hot, sunny day. On a cold day, an ectotherm might bask in the sun to warm up, like the snake in Figure below . Almost all living fish, amphibians, and reptiles are ectothermic. They can raise or lower their body temperature by their behavior but not by very much. In cold weather, an ectotherm cools down. As its body temperature drops, its metabolism slows down and it becomes inactive. Q: What type of vertebrates control body temperature to just a limited extent from the outside by changing behavior? Choices: - etheric - endothermic - mimetic - ectothermic A:
ectothermic
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Answer the following question given this paragraph: Q: In the humoral response, what protein substances help neutralize or eliminate toxins and pathogens in the blood and lymph? Choices: - platelets - membranes - parasites - antibodies A:
antibodies
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