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A horse and a donkey produce a mule. Which description identifies the process that produced this offspring? A. Isolation of two populations before mating can occur B. Asexual reproduction from one parent C. Interbreeding between members of different species D.…
A unicellular Euglena culture fixes carbon in light but can also obtain organic nutrients from its surroundings. Which description covers both modes? A. Obligate carnivore only B. Obligate saprotroph only C. Obligate photoautotroph only D. Mixotroph
Two species have almost identical requirements for a limiting resource. In a constant environment, one consistently uses that resource more efficiently. Which outcome illustrates competitive exclusion? A. Predation must always increase until both competitors…
Which climatic description is most consistent with tundra? A. Low annual precipitation, long cold winters and a short growing season B. High rainfall and high temperatures throughout the year C. High rainfall and frost-free conditions throughout the year D.…
Arrows in this food web point from food to consumer. How many animal species feed exclusively as primary consumers in the web shown? A. 5 B. 4 C. 6 D. 3
Ecologists mark 84 woodlice and return them to a study site. After mixing, a second sample contains 72 woodlice, of which 18 are marked. Using N = MC/R, what is the estimated population? A. 174 B. 336 C. 6048 D. 1512
Photosynthetic symbionts live within a reef-building coral. Which transfer provides a benefit to the symbionts? A. Carbon dioxide released by coral respiration supplies carbon for photosynthesis B. Coral cells provide sunlight by respiration C. The symbionts…
A model for a northern-hemisphere station combines a rising long-term trend with annual carbon-dioxide decreases. Which seasonal change contributes most directly to the decreases? A. An increase in decomposition B. An increase in combustion C. An increase in…
A microorganism fixes carbon dioxide using energy released when it oxidises hydrogen sulfide. Which nutritional category fits this organism? A. Photoheterotroph B. Saprotrophic heterotroph C. Chemoautotroph D. Photoautotroph
In an iron-limited marine region, adding iron briefly stimulates phytoplankton growth. What is a plausible immediate consequence? A. Reduced primary production because the limiting nutrient was added B. Increased photosynthetic uptake of carbon dioxide from…