Problem: Predators play an important role in an ecosystem. For example, if they did not exist, then a single species could become dominant over others. Grazers on a grassland keep grass from growing out of control. Predators can be keystone species . These are species that can have a large effect on the balance of organisms in an ecosystem. For example, if all of the wolves are removed from a population, then the population of deer or rabbits may increase. If there are too many deer, then they may decrease the amount of plants or grasses in the ecosystem. Decreased levels of producers may then have a detrimental effect on the whole ecosystem. In this example, the wolves would be a keystone species. Dan and Joe studied animals for biology class. Joe had to study predator animals, while Dan studied herbivores and grazers. Which student learned more about potential keystone species?

A: Dan

Problem: Given the question: Protozoa generally feed by engulfing and digesting other organisms. As consumers, they have various roles in food chains and webs. Some are predators. They prey upon other single-celled organisms, such as bacteria. In fact, protozoa predators keep many bacterial populations in check. Other protozoa are herbivores. They graze on algae. Still others are decomposers. They consume dead organic matter. There are also parasitic protozoa that live in or on living hosts. For example, the protozoan that causes malaria lives inside a human host. For their part, protozoa are important food sources for many larger organisms, including insects and worms. Two biologists studied different living creatures. Matt studied protozoa, while his friend Greg studied nematodes and insects. Which friend studied less about herbivore protozoa?
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The answer is:
Greg

input question: A comet tailand comaare features visible in comets when they are illuminated by the Sun and may become visible from Earth when a comet passes through the inner Solar System. As a comet approaches the inner Solar System, solar radiation causes the volatile materials within the comet to vaporize and stream out of the nucleus, carrying dust away with them. Separate tails are formed of dust and gases, becoming visible through different phenomena; the dust reflects sunlight directly and the gases glow from ionisation. Most comets are too faint to be visible without the aid of a telescope, but a few each decade become bright enough to be visible to the naked eye. This year thee comets would be of interest, comet A, comet B, and comet C. Comet A and comet B would enter the inner solar system. But comet C would not enter the inner solar system. Moreover, comet A is categorized as a bright comet, but comet B is categorized as a faint comet. Whcih comet would not be visible to naked eye, comet A or comet B????
output answer: comet B

Ecologically, the expansion of drainage systems has had tremendous negative effects. Hundreds of thousands of wetland species experienced significant population declines as their habitat was increasingly fragmented and destroyed. Although market hunting within the Central Flyway was a contributing factor in the decline of many waterfowl species' numbers in the early decades of the twentieth century, loss of breeding habitat to agricultural expansion is certainly the most significant. Early maps of midwestern states depict many lakes and marshes that are either nonexistent or significantly reduced in area today. Channelization, a related process of concentrating and facilitating the flow of water from agricultural areas, also contributed to this degradation. Timber village started a channelization process by draining all the swamps near their village. Hill village situated 10 miles to the south, left their swamps untouched. Which village experienced no decline in waterfowl species?
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Answer: Hill

Q: The major effect of transpiration is the reduction of soil pore water pressures which counteracts the loss of strength which occurs through wetting, this is most readily seen as a loss of moisture around trees. However it is not easy to rely on tree and shrub roots to remove water from slopes and consequently help ensure slope stability. The ability to transpire in wet conditions is severely reduced and therefore any increase in soil strength previously gained in evaporation and transpiration will be lost or significantly reduced, consequently the effects of transpiration cannot be taken into account at these times. However it can be assumed that the chance of slope failure following saturation by storm event or periods of extended rainfall will be lessened as a result of transpiration. Moreover, although changes in moisture content will affect the undrained shear strength, the effective shear stress parameters as commonly used in routine slope stability analysis are not directly influenced by changing moisture content, although the water pressures (suctions) used in the analysis will change.[2][3] The two teams took different approaches in reinforcing the highway embankment slopes when building segments of the interstate. Team A led by Chuck relied almost entirely on inspiration and good building materials therefore decreasing slope stability, while team B lead by Mike used nature as an ally by planting tens of thousands of trees and shrubs to prevent slope failures and moderate soil transpiration and evaporation. Will the slope built by team B hold more or less stormwater than the slope built by team A?
A: more

[Q]: Lake-effect snow is produced during cooler atmospheric conditions when a cold air mass moves across long expanses of warmer lake water, warming the lower layer of air which picks up water vapor from the lake, rises up through the colder air above, freezes and is deposited on the leeward (downwind) shores.[1] The same effect also occurs over bodies of salt water, when it is termed ocean-effect or bay-effect snow. The effect is enhanced when the moving air mass is uplifted by the orographic influence of higher elevations on the downwind shores. This uplifting can produce narrow but very intense bands of precipitation, which deposit at a rate of many inches of snow each hour, often resulting in a large amount of total snowfall. Hammond and Trip were two cities on the Eastern and Western shores of lake Michigan. They both get lots of snow during winter, but the lake effect snow which adds feet of snow to the yearly total, lingers much longer on the eastern side of the lake. Which city has fewer snow days during winter?
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[A]:
Trip