Practice Quiz Mode
Take all 3 MCQs in interactive quiz mode with timer and progress tracking
| Average Nitrate and Phosphate Concentrations in Seawater after Volcanic Eruption | ||||
|---|---|---|---|---|
| Nutrient | Seawater in lava-affected area, 5-45 meters below surface | Seawater in lava-affected area, 75-125 meters below surface | Seawater outside of lava-affected area, 5-45 meters below surface | Seawater outside of lava-affected area, 75-125 meters below surface |
| Nitrate (micromoles per liter) | 3.1 | 0.4 | ≤0.03 | ≤0.01 |
| Phosphate (micromoles per liter) | 0.17 | 0.09 | 0.14 | 0.06 |
After a volcanic eruption spilled lava into North Pacific Ocean waters, a dramatic increase of diatoms (a kind of phytoplankton) near the surface occurred. Scientists assumed the diatoms were thriving on nutrients such as phosphate from the lava, but analysis showed these nutrients weren't present near the surface in forms diatoms can consume. However, there was an abundance of usable nitrate, a nutrient usually found in much deeper water and almost never found in lava. Microbial oceanographer Sonya Dyhrman and colleagues believe that as the lava plunged nearly 300 meters below the surface it dislodged pockets of this nutrient, releasing it to float upward, given that _______
Which choice most effectively uses data from the table to complete the statement?
at 5-45 meters below the surface, the average concentration of phosphate was about the same in the seawater in the lava-affected area as in the seawater outside of the lava-affected area.
for both depth ranges measured, the average concentrations of nitrate were substantially higher in the seawater in the lava-affected area than in the seawater outside of the lava-affected area.
for both depth ranges measured in the seawater in the lava-affected area, the average concentrations of nitrate were substantially higher than the average concentrations of phosphate.
in the seawater outside of the lava-affected area, there was little change in the average concentration of nitrate from 75-125 meters below the surface to 5-45 meters below the surface.
North American gray wolves usually have mixed gray and white fur, but some members of the species have a version of a gene, or gene variant, that gives them a mostly black coat instead. Sarah Cubaynes and her team studied twelve populations of North American gray wolves. They found that the black-furred wolves are more common in areas where outbreaks of distemper virus happen regularly. The team also discovered that the black-furred wolves are more likely to be immune to distemper than the gray-furred wolves are. Taken together, these findings suggest that _______
Which choice most logically completes the text?
North American gray wolves experience more outbreaks of distemper virus than other wolf species do.
the gene variant that results in black fur may be linked to immunity to the distemper virus.
the average life span of gray wolves is likely to increase over time because of a particular gene variant.
gray-furred wolves will soon replace black-furred wolves across North America.
If some artifacts recovered from excavations of the settlement of Kuulo Kataa, in modern Ghana, date from the thirteenth century CE, that may lend credence to claims that the settlement was founded before or around that time. There is other evidence, however, strongly supporting a fourteenth century CE founding date for Kuulo Kataa. If both the artifact dates and the fourteenth century CE founding date are correct, that would imply that ________
Which choice most logically completes the text?
artifacts from the fourteenth century CE are more commonly recovered than are artifacts from the thirteenth century CE.
the artifacts originated elsewhere and eventually reached Kuulo Kataa through trade or migration.
Kuulo Kataa was founded by people from a different region than had previously been assumed.
excavations at Kuulo Kataa may have inadvertently damaged some artifacts dating to the fourteenth century CE.
Unlock Premium Content
Sign in and upgrade to continue reading this premium post.