Two teams studied two types of animals: team A studied predators, while team B studied grazers. They learned a lot from this experience. Which team learned that predators play an important role in an ecosystem? Hint: 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.
Ans: team A

Two coffee farms used different methods to grow coffee. Hill farm grown coffee conventionally, while Valley farm is into shade-grown coffee production. Which farm grew less coffee with improved quality? Hint: With shade applications, crops are purposely raised under tree canopies within the shady environment. The understory crops are shade tolerant or the overstory trees have fairly open canopies. A conspicuous example is shade-grown coffee. This practice reduces weeding costs and improves coffee quality and taste. The shade does not necessarily translate into lost or reduced yields. This is because the rate of photosynthesis hardly increases once the light intensity is over about one tenth that of direct overhead sunlight and declines with increasing light intensity. This means that shaded plants can grow well. Planting more than one level of vegetation can increase total photosynthesis and overall yields.
Ans: Hill

Two farms were situated on opposite banks of a large river flowing into the ocean. Hill farm practiced conventional agriculture, while Dew farm practiced permaculture design within the context of organic farming. Which farm generated more marine pollution? Hint: Marine pollution is a generic term for the entry into the ocean of potentially hazardous chemicals or particles. The biggest culprits are rivers and with them many agriculture fertilizer chemicals as well as livestock and human waste. The excess of oxygen-depleting chemicals leads to hypoxia and the creation of a dead zone.Marine debris, which is also known as marine litter, describes human-created waste floating in a body of water. Oceanic debris tends to accumulate at the center of gyres and coastlines, frequently washing aground where it is known as beach litter.
Ans: Hill

Mark is doing an experiment creating a magnet. He takes a piece of iron named iron bar A and wraps it in a coil of copper wire. After that he puts an electric current through the copper for about an hour. Given Mark disconnects and unwraps the copper wire, will the magnetic strength of the iron bar have increased or decreased? Hint: Our knowledge of electromagnets developed from a series of observations. In 1820, Hans Oersted discovered that a current-carrying wire produced a magnetic field. Later in the same year, Andre-Marie Ampere discovered that a coil of wire acted like a permanent magnet and Francois Arago found that an iron bar could be magnetized by putting it inside of a coil of current-carrying wire. Finally, William Sturgeon found that leaving the iron bar inside the coil greatly increased the magnetic field.
Ans: increased